diff --git a/README.md b/README.md
index b721c97..8048c7b 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,7 @@ struct BasicApp {
 }
 
 impl AppDelegate for BasicApp {
-    fn did_finish_launching(&mut self) {
+    fn did_finish_launching(&self) {
         self.window.set_minimum_content_size(400., 400.);
         self.window.set_title("Hello World!");
         self.window.show();
diff --git a/examples/defaults.rs b/examples/defaults.rs
index d3896ee..f7db861 100644
--- a/examples/defaults.rs
+++ b/examples/defaults.rs
@@ -3,7 +3,8 @@
 use std::collections::HashMap;
 
 use cacao::macos::app::{App, AppDelegate};
-use cacao::defaults::{UserDefaults, DefaultValue};
+use cacao::defaults::{UserDefaults, Value};
+use cacao::foundation::NSData;
 
 #[derive(Default)]
 struct DefaultsTest;
@@ -14,16 +15,39 @@ impl AppDelegate for DefaultsTest {
 
         defaults.register({
             let mut map = HashMap::new();
-            map.insert("LOL", DefaultValue::string("laugh"));
-            map.insert("X", DefaultValue::Integer(1));
-            map.insert("X2", DefaultValue::Float(1.0));
-            map.insert("BOOL", DefaultValue::bool(true));
+            //map.insert("LOL", Value::string("laugh"));
+            //map.insert("X", Value::Integer(1));
+            //map.insert("X2", Value::Float(1.0));
+            map.insert("BOOL", Value::bool(true));
+
+            println!("Test equivalency:");
+            let s = "BYTES TEST".to_string().into_bytes();
+            println!("    {:?}", s);
+            let x = NSData::new(s);
+            println!("    {:?}", x.bytes());
+            
+            let s2 = "BYTES TEST".to_string().into_bytes();
+            map.insert("BYTES", Value::Data(s2));
+            
             map
         });
 
-        println!("Retrieved LOL: {:?}", defaults.get("LOL"));
-        println!("Retrieved LOL: {:?}", defaults.get("X"));
-        println!("Retrieved LOL: {:?}", defaults.get("X2"));
+        //println!("Retrieved LOL: {:?}", defaults.get("LOL"));
+        //println!("Retrieved LOL: {:?}", defaults.get("X"));
+        //println!("Retrieved LOL: {:?}", defaults.get("X2"));
+
+        let bytes = defaults.get("BYTES").unwrap();
+        println!("Bytes: {:?}", bytes);
+        let data = match std::str::from_utf8(bytes.as_data().unwrap()) {
+            Ok(s) => s,
+            Err(e) => {
+                eprintln!("Error converting bytes {}", e);
+                "Error converting bytes"
+            }
+        };
+
+        println!("Retrieved Bytes: {}", data);
+        
 
         App::terminate();
     }
diff --git a/src/defaults/mod.rs b/src/defaults/mod.rs
index c0b3147..34b1d6c 100644
--- a/src/defaults/mod.rs
+++ b/src/defaults/mod.rs
@@ -1,7 +1,7 @@
 //! Wraps `NSUserDefaults`, providing an interface to fetch and store small amounts of data.
 //!
 //! In general, this tries to take an approach popularized by `serde_json`'s `Value` struct. In
-//! this case, `DefaultValue` handles wrapping types for insertion/retrieval, shepherding between
+//! this case, `Value` handles wrapping types for insertion/retrieval, shepherding between
 //! the Objective-C runtime and your Rust code.
 //!
 //! It currently supports a number of primitive types, as well as a generic `Data` type for custom
@@ -17,13 +17,13 @@
 //! ## Example
 //! ```rust
 //! use std::collections::HashMap;
-//! use cacao::defaults::{UserDefaults, DefaultValue};
+//! use cacao::defaults::{UserDefaults, Value};
 //!
 //! let mut defaults = UserDefaults::standard();
 //!
 //! defaults.register({
 //!     let map = HashMap::new();
-//!     map.insert("test", DefaultValue::string("value"));
+//!     map.insert("test", Value::string("value"));
 //!     map
 //! });
 //!
@@ -33,18 +33,15 @@
 //! ```
 
 use std::collections::HashMap;
-use std::ffi::CStr;
-use std::os::raw::c_char;
-use std::unreachable;
 
 use objc::{class, msg_send, sel, sel_impl};
 use objc::runtime::Object;
 use objc_id::Id;
 
-use crate::foundation::{id, nil, YES, BOOL, NSInteger, NSString, NSDictionary};
+use crate::foundation::{id, nil, YES, BOOL, NSData, NSInteger, NSString, NSDictionary, NSNumber};
 
 mod value;
-pub use value::DefaultValue;
+pub use value::Value;
 
 /// Wraps and provides methods for interacting with `NSUserDefaults`, which can be used for storing
 /// pieces of information (preferences, or _defaults_) to persist across application launches.
@@ -106,17 +103,17 @@ impl UserDefaults {
     /// ```rust
     /// use std::collections::HashMap;
     ///
-    /// use cacao::defaults::{UserDefaults, DefaultValue};
+    /// use cacao::defaults::{UserDefaults, Value};
     ///
     /// let mut defaults = UserDefaults::standard();
     /// 
     /// defaults.register({
     ///     let mut map = HashMap::new();
-    ///     map.insert("test", DefaultValue::Bool(true));
+    ///     map.insert("test", Value::Bool(true));
     ///     map
     /// });
     /// ```
-    pub fn register<K: AsRef<str>>(&mut self, values: HashMap<K, DefaultValue>) {
+    pub fn register<K: AsRef<str>>(&mut self, values: HashMap<K, Value>) {
         let dictionary = NSDictionary::from(values);
         
         unsafe {
@@ -128,14 +125,14 @@ impl UserDefaults {
     /// `NSUserDefaults` store, and asynchronously persists to the disk.
     ///
     /// ```rust
-    /// use cacao::defaults::{UserDefaults, DefaultValue};
+    /// use cacao::defaults::{UserDefaults, Value};
     ///
     /// let mut defaults = UserDefaults::standard();
-    /// defaults.insert("test", DefaultValue::Bool(true));
+    /// defaults.insert("test", Value::Bool(true));
     /// ```
-    pub fn insert<K: AsRef<str>>(&mut self, key: K, value: DefaultValue) {
+    pub fn insert<K: AsRef<str>>(&mut self, key: K, value: Value) {
         let key = NSString::new(key.as_ref());
-        let value: id = (&value).into();
+        let value: id = value.into();
 
         unsafe {
             let _: () = msg_send![&*self.0, setObject:value forKey:key];
@@ -145,7 +142,7 @@ impl UserDefaults {
     /// Remove the default associated with the key. If the key doesn't exist, this is a noop.
     ///
     /// ```rust
-    /// use cacao::defaults::{UserDefaults, DefaultValue};
+    /// use cacao::defaults::{UserDefaults, Value};
     ///
     /// let mut defaults = UserDefaults::standard();
     /// defaults.remove("test");
@@ -158,7 +155,7 @@ impl UserDefaults {
         }
     }
 
-    /// Returns a `DefaultValue` for the given key, from which you can further extract the data you
+    /// Returns a `Value` for the given key, from which you can further extract the data you
     /// need. Note that this does a `nil` check and will return `None` in such cases, with the
     /// exception of `bool` values, where it will always return either `true` or `false`. This is
     /// due to the underlying storage engine used for `NSUserDefaults`.
@@ -167,15 +164,15 @@ impl UserDefaults {
     /// returns new immutable copies each time, so we're free to vend them as such.
     ///
     /// ```rust
-    /// use cacao::defaults::{UserDefaults, DefaultValue};
+    /// use cacao::defaults::{UserDefaults, Value};
     ///
     /// let mut defaults = UserDefaults::standard();
-    /// defaults.insert("test", DefaultValue::string("value"));
+    /// defaults.insert("test", Value::string("value"));
     ///
     /// let value = defaults.get("test").unwrap().as_str().unwrap();
     /// assert_eq!(value, "value");
     /// ```
-    pub fn get<K: AsRef<str>>(&self, key: K) -> Option<DefaultValue> {
+    pub fn get<K: AsRef<str>>(&self, key: K) -> Option<Value> {
         let key = NSString::new(key.as_ref());
 
         let result: id = unsafe {
@@ -186,36 +183,32 @@ impl UserDefaults {
             return None;
         }
 
-        let is_string: BOOL = unsafe { msg_send![result, isKindOfClass:class!(NSString)] };
-        if is_string == YES {
+        if NSData::is(result) {
+            let data = NSData::wrap(result);
+            return Some(Value::Data(data.into_vec()));
+        }
+
+        if NSString::is(result) {
             let s = NSString::wrap(result).to_str().to_string();
-            return Some(DefaultValue::String(s));
+            return Some(Value::String(s));
         }
 
         // This works, but might not be the best approach. We basically need to inspect the
         // `NSNumber` returned and see what the wrapped encoding type is. `q` and `d` represent
         // `NSInteger` (platform specific) and `double` (f64) respectively, but conceivably we
         // might need others.
-        let is_number: BOOL = unsafe { msg_send![result, isKindOfClass:class!(NSNumber)] };
-        if is_number == YES {
-            unsafe {
-                let t: *const c_char = msg_send![result, objCType];
-                let slice = CStr::from_ptr(t);
+        if NSNumber::is(result) {
+            let number = NSNumber::wrap(result);
+            
+            return match number.objc_type() {
+                "q" => Some(Value::Integer(number.as_i64())),
+                "d" => Some(Value::Float(number.as_f64())),
 
-                if let Ok(code) = slice.to_str() {
-                    println!("Code: {}", code);
-
-                    if code == "q" {
-                        let v: NSInteger = msg_send![result, integerValue];
-                        return Some(DefaultValue::Integer(v as i64));
-                    }
-
-                    if code == "d" {
-                        let v: f64 = msg_send![result, doubleValue];
-                        return Some(DefaultValue::Float(v));
-                    }
+                _ => {
+                    // @TODO: Verify this area.
+                    None
                 }
-            }
+            };
         }
 
         None
diff --git a/src/defaults/value.rs b/src/defaults/value.rs
index d9c619e..d53df96 100644
--- a/src/defaults/value.rs
+++ b/src/defaults/value.rs
@@ -1,35 +1,44 @@
-//! 
-
 use std::collections::HashMap;
 
 use objc::{class, msg_send, sel, sel_impl};
 use objc_id::Id;
 
-use crate::foundation::{id, YES, NO, nil, NSInteger, NSDictionary, NSString};
+use crate::foundation::{id, YES, NO, NSData, NSInteger, NSDictionary, NSString};
 
+/// Represents a Value that can be stored or queried with `UserDefaults`.
+///
+/// In general, this wraps a few types that should hopefully work for most cases. Note that the
+/// `Value` always owns whatever it holds - this is both for ergonomic considerations, as
+/// well as contractual obligations with the underlying `NSUserDefaults` system.
 #[derive(Clone, Debug, PartialEq)]
-pub enum DefaultValue {
+pub enum Value {
+    /// Represents a Boolean value.
     Bool(bool),
+
+    /// Represents a String value.
     String(String),
+
+    /// Represents a Float (`f64`) value.
     Float(f64),
-    Integer(i64)
+
+    /// Represents an Integer (`i64`) value.
+    Integer(i64),
+
+    /// Represents Data (bytes). You can use this to store arbitrary things that aren't supported
+    /// above. You're responsible for moving things back and forth to the necessary types.
+    Data(Vec<u8>)
 }
 
-impl DefaultValue {
-    /// A handy initializer for `DefaultValue::Bool`.
-    pub fn bool(value: bool) -> Self {
-        DefaultValue::Bool(value)
-    }
-
-    /// A handy initializer for `DefaultValue::String`;
+impl Value {
+    /// A handy initializer for `Value::String`.
     pub fn string<S: Into<String>>(value: S) -> Self {
-        DefaultValue::String(value.into())
+        Value::String(value.into())
     }
     
     /// Returns `true` if the value is a boolean value. Returns `false` otherwise.
     pub fn is_boolean(&self) -> bool {
         match self {
-            DefaultValue::Bool(_) => true,
+            Value::Bool(_) => true,
             _ => false
         }
     }
@@ -37,7 +46,7 @@ impl DefaultValue {
     /// If this is a Bool, it returns the associated bool. Returns `None` otherwise.
     pub fn as_bool(&self) -> Option<bool> {
         match self {
-            DefaultValue::Bool(v) => Some(*v),
+            Value::Bool(v) => Some(*v),
             _ => None
         }
     }
@@ -45,7 +54,7 @@ impl DefaultValue {
     /// Returns `true` if the value is a string. Returns `false` otherwise.
     pub fn is_string(&self) -> bool {
         match self {
-            DefaultValue::String(_) => true,
+            Value::String(_) => true,
             _ => false
         }
     }
@@ -53,7 +62,7 @@ impl DefaultValue {
     /// If this is a String, it returns a &str. Returns `None` otherwise.
     pub fn as_str(&self) -> Option<&str> {
         match self {
-            DefaultValue::String(s) => Some(s),
+            Value::String(s) => Some(s),
             _ => None
         }
     }
@@ -61,7 +70,7 @@ impl DefaultValue {
     /// Returns `true` if the value is a float. Returns `false` otherwise.
     pub fn is_integer(&self) -> bool {
         match self {
-            DefaultValue::Integer(_) => true,
+            Value::Integer(_) => true,
             _ => false
         }
     }
@@ -69,7 +78,7 @@ impl DefaultValue {
     /// If this is a int, returns it (`i32`). Returns `None` otherwise.
     pub fn as_i32(&self) -> Option<i32> {
         match self {
-            DefaultValue::Integer(i) => Some(*i as i32),
+            Value::Integer(i) => Some(*i as i32),
             _ => None
         }
     }
@@ -77,7 +86,7 @@ impl DefaultValue {
     /// If this is a int, returns it (`i64`). Returns `None` otherwise.
     pub fn as_i64(&self) -> Option<i64> {
         match self {
-            DefaultValue::Integer(i) => Some(*i as i64),
+            Value::Integer(i) => Some(*i as i64),
             _ => None
         }
     }
@@ -85,7 +94,7 @@ impl DefaultValue {
     /// Returns `true` if the value is a float. Returns `false` otherwise.
     pub fn is_float(&self) -> bool {
         match self {
-            DefaultValue::Float(_) => true,
+            Value::Float(_) => true,
             _ => false
         }
     }
@@ -93,7 +102,7 @@ impl DefaultValue {
     /// If this is a float, returns it (`f32`). Returns `None` otherwise.
     pub fn as_f32(&self) -> Option<f32> {
         match self {
-            DefaultValue::Float(f) => Some(*f as f32),
+            Value::Float(f) => Some(*f as f32),
             _ => None
         }
     }
@@ -101,42 +110,60 @@ impl DefaultValue {
     /// If this is a float, returns it (`f64`). Returns `None` otherwise.
     pub fn as_f64(&self) -> Option<f64> {
         match self {
-            DefaultValue::Float(f) => Some(*f as f64),
+            Value::Float(f) => Some(*f as f64),
+            _ => None
+        }
+    }
+
+    /// Returns `true` if the value is data. Returns `false` otherwise.
+    pub fn is_data(&self) -> bool {
+        match self {
+            Value::Data(_) => true,
+            _ => false
+        }
+    }
+
+    /// If this is data, returns it (`&[u8]`). If you need to own the underlying buffer, you can
+    /// extract it yourself. Returns `None` if this is not Data.
+    pub fn as_data(&self) -> Option<&[u8]> {
+        match self {
+            Value::Data(data) => Some(data),
             _ => None
         }
     }
 }
 
-impl From<&DefaultValue> for id {
-    /// Shepherds `DefaultValue` types into `NSObject`s that can be stored in `NSUserDefaults`.
+impl From<Value> for id {
+    /// Shepherds `Value` types into `NSObject`s that can be stored in `NSUserDefaults`.
     // These currently work, but may not be exhaustive and should be looked over past the preview
     // period.
-    fn from(value: &DefaultValue) -> Self {
+    fn from(value: Value) -> Self {
         unsafe {
             match value {
-                DefaultValue::Bool(b) => msg_send![class!(NSNumber), numberWithBool:match b {
+                Value::Bool(b) => msg_send![class!(NSNumber), numberWithBool:match b {
                     true => YES,
                     false => NO
                 }],
 
-                DefaultValue::String(s) => NSString::new(&s).into_inner(),
-                DefaultValue::Float(f) => msg_send![class!(NSNumber), numberWithDouble:*f],
-                DefaultValue::Integer(i) => msg_send![class!(NSNumber), numberWithInteger:*i as NSInteger]
+                Value::String(s) => NSString::new(&s).into_inner(),
+                Value::Float(f) => msg_send![class!(NSNumber), numberWithDouble:f],
+                Value::Integer(i) => msg_send![class!(NSNumber), numberWithInteger:i as NSInteger],
+                Value::Data(data) => NSData::new(data).into_inner()
             }
         }
     }
 }
 
-impl<K> From<HashMap<K, DefaultValue>> for NSDictionary
+impl<K> From<HashMap<K, Value>> for NSDictionary
 where
     K: AsRef<str>
 {
-    /// Translates a `HashMap` of `DefaultValue`s into an `NSDictionary`.
-    fn from(map: HashMap<K, DefaultValue>) -> Self {
+    /// Translates a `HashMap` of `Value`s into an `NSDictionary`.
+    fn from(map: HashMap<K, Value>) -> Self {
         NSDictionary(unsafe {
             let dictionary: id = msg_send![class!(NSMutableDictionary), new];
 
-            for (key, value) in map.iter() {
+            for (key, value) in map.into_iter() {
                 let k = NSString::new(key.as_ref()); 
                 let v: id = value.into();
                 let _: () = msg_send![dictionary, setObject:v forKey:k];
diff --git a/src/foundation/data.rs b/src/foundation/data.rs
new file mode 100644
index 0000000..193dfa7
--- /dev/null
+++ b/src/foundation/data.rs
@@ -0,0 +1,129 @@
+//! A wrapper for `NSData`.
+//!
+//! This more or less exists to try and wrap the specific APIs we use to interface with Cocoa. Note
+//! that in general this is only concerned with bridging for arguments - i.e, we need an `NSData`
+//! from a `Vec<u8>` to satisfy the Cocoa side of things. It's expected that all processing of data
+//! happens solely on the Rust side of things before coming through here.
+//!
+//! tl;dr this is an intentionally limited API.
+
+use std::mem;
+use std::os::raw::c_void;
+use std::slice;
+
+use block::{Block, ConcreteBlock};
+
+use objc::{class, msg_send, sel, sel_impl};
+use objc::runtime::Object;
+use objc_id::Id;
+
+use crate::foundation::{id, BOOL, YES, NO, NSUInteger};
+
+/// Wrapper for a retained `NSData` object.
+///
+/// Supports constructing a new `NSData` from a `Vec<u8>`, wrapping and retaining an existing
+/// pointer from the Objective-C side, and turning an `NSData` into a `Vec<u8>`.
+#[derive(Debug)]
+pub struct NSData(pub Id<Object>);
+
+impl NSData {
+    /// Given a vector of bytes, creates, retains, and returns a wrapped `NSData`.
+    ///
+    /// This method is borrowed straight out of [objc-foundation](objc-foundation) by the amazing
+    /// Steven Sheldon, and just tweaked slightly to fit the desired API semantics here.
+    ///
+    /// [objc-foundation]: https://crates.io/crates/objc-foundation
+    pub fn new(bytes: Vec<u8>) -> Self {
+        let capacity = bytes.capacity();
+
+        let dealloc = ConcreteBlock::new(move |bytes: *mut c_void, len: usize| unsafe {
+            // Recreate the Vec and let it drop
+            let _ = Vec::from_raw_parts(bytes as *mut u8, len, capacity);
+        });
+        let dealloc = dealloc.copy();
+        let dealloc: &Block<(*mut c_void, usize), ()> = &dealloc;
+
+        let mut bytes = bytes;
+        let bytes_ptr = bytes.as_mut_ptr() as *mut c_void;
+
+        unsafe {
+            let obj: id = msg_send![class!(NSData), alloc];
+            let obj: id = msg_send![obj, initWithBytesNoCopy:bytes_ptr
+                                                             length:bytes.len()
+                                                        deallocator:dealloc];
+            mem::forget(bytes);
+            NSData(Id::from_ptr(obj))
+        }
+    }
+
+    /// If we're vended an NSData from a method (e.g, a push notification token) we might want to
+    /// wrap it while we figure out what to do with it. This does that.
+    pub fn wrap(data: id) -> Self {
+        NSData(unsafe {
+            Id::from_ptr(data)
+        })
+    }
+
+    /// A helper method for determining if a given `NSObject` is an `NSData`.
+    pub fn is(obj: id) -> bool {
+        let result: BOOL = unsafe {
+            msg_send![obj, isKindOfClass:class!(NSData)]
+        };
+
+        match result {
+            YES => true,
+            NO => false,
+            _ => unreachable!()
+        }
+    }
+
+    /// Returns the length of the underlying `NSData` bytes.
+    pub fn len(&self) -> usize {
+        unsafe {
+            let x: NSUInteger = msg_send![&*self.0, length];
+            x as usize
+        }
+    }
+    
+    /// Returns a reference to the underlying bytes for the wrapped `NSData`.
+    ///
+    /// This, like `NSData::new()`, is cribbed from [objc-foundation](objc-foundation).
+    ///
+    /// [objc-foundation](https://crates.io/crates/objc-foundation)
+    pub fn bytes(&self) -> &[u8] {
+        let ptr: *const c_void = unsafe { msg_send![&*self.0, bytes] };
+        
+        // The bytes pointer may be null for length zero
+        let (ptr, len) = if ptr.is_null() {
+            (0x1 as *const u8, 0)
+        } else {
+            (ptr as *const u8, self.len())
+        };
+        
+        unsafe {
+            slice::from_raw_parts(ptr, len)
+        }
+    }
+    
+    /// Creates a new Vec, copies the NSData (safely, but quickly) bytes into that Vec, and
+    /// consumes the NSData enabling it to release (provided nothing in Cocoa is using it).
+    ///
+    // A point of discussion: I think this is the safest way to handle it, however I could be
+    // wrong - it's a bit defensive but I can't think of a way to reliably return an owned set of
+    // this data without messing up the Objective-C side of things. Thankfully this isn't used too
+    // often, but still... open to ideas.
+    pub fn into_vec(self) -> Vec<u8> {
+        let mut data = Vec::new();
+        
+        let bytes = self.bytes();
+        data.resize(bytes.len(), 0);
+        data.copy_from_slice(bytes);
+        
+        data
+    }
+
+    /// Consumes and returns the underlying `NSData`.
+    pub fn into_inner(mut self) -> id {
+        &mut *self.0
+    }
+}
diff --git a/src/foundation/dictionary.rs b/src/foundation/dictionary.rs
index 5de3879..bf6b9b2 100644
--- a/src/foundation/dictionary.rs
+++ b/src/foundation/dictionary.rs
@@ -5,7 +5,7 @@ use objc::{class, msg_send, sel, sel_impl};
 use objc::runtime::Object;
 use objc_id::Id;
 
-use crate::foundation::{id, nil, YES, NO, NSString};
+use crate::foundation::id;
 
 /// A wrapper for `NSDictionary`. Behind the scenes we actually wrap `NSMutableDictionary`, and
 /// rely on Rust doing the usual borrow-checking guards that it does so well.
diff --git a/src/foundation/mod.rs b/src/foundation/mod.rs
index ee6db9b..11e5165 100644
--- a/src/foundation/mod.rs
+++ b/src/foundation/mod.rs
@@ -1,5 +1,6 @@
-//! This module contains some lightweight wrappers over certain data types that we use throughout
-//! the framework. Some of it is pulled/inspired from Servo's cocoa-rs (e.g, the "id" type). While
+//! This module contains some lightweight wrappers over Foundation data types.
+//!
+//! Some of it is pulled/inspired from Servo's cocoa-rs (e.g, the "id" type). While
 //! this isn't a clone of their module (we don't need everything from there, but remaining
 //! compatible in case an end-user wants to drop that low is deal), it's worth linking their
 //! license and repository - they've done really incredible work and it's 100% worth acknowledging.
@@ -7,6 +8,12 @@
 //! - [core-foundation-rs Repository](https://github.com/servo/core-foundation-rs)
 //! - [core-foundation-rs MIT License](https://github.com/servo/core-foundation-rs/blob/master/LICENSE-MIT)
 //! - [core-foundation-rs Apache License](https://github.com/servo/core-foundation-rs/blob/master/LICENSE-APACHE)
+//!
+//! ## Why?
+//! A good question. The existing wrappers tend to use traits over `id`, which works well for some
+//! cases, but I found it frustrating and messy trying to work with them. These provide the API I
+//! was looking for, and help provide all the proper `retain`/`release` logic needed for the
+//! Objective-C side.
 
 #![allow(non_camel_case_types)]
 #![allow(non_upper_case_globals)]
@@ -14,30 +21,44 @@
 use objc::runtime;
 pub use objc::runtime::{BOOL, NO, YES};
 
-pub mod autoreleasepool;
+mod autoreleasepool;
 pub use autoreleasepool::AutoReleasePool;
 
-pub mod array;
+mod array;
 pub use array::NSArray;
 
-pub mod string;
-pub use string::NSString;
+mod data;
+pub use data::NSData;
 
-pub mod dictionary;
+mod dictionary;
 pub use dictionary::NSDictionary;
 
+mod number;
+pub use number::NSNumber;
+
+mod string;
+pub use string::NSString;
+
+/// More or less maps over to Objective-C's `id` type, which... can really be anything.
 #[allow(non_camel_case_types)]
 pub type id = *mut runtime::Object;
 
+/// Exactly what it sounds like.
 #[allow(non_upper_case_globals)]
 pub const nil: id = 0 as id;
 
+/// Platform-specific.
 #[cfg(target_pointer_width = "32")]
 pub type NSInteger = libc::c_int;
+
+/// Platform-specific.
 #[cfg(target_pointer_width = "32")]
 pub type NSUInteger = libc::c_uint;
 
+/// Platform-specific.
 #[cfg(target_pointer_width = "64")]
 pub type NSInteger = libc::c_long;
+
+/// Platform-specific.
 #[cfg(target_pointer_width = "64")]
 pub type NSUInteger = libc::c_ulong;
diff --git a/src/foundation/number.rs b/src/foundation/number.rs
new file mode 100644
index 0000000..e44ec45
--- /dev/null
+++ b/src/foundation/number.rs
@@ -0,0 +1,88 @@
+//! A wrapper for `NSNumber`.
+//!
+//! There are a few places where we have to interact with this type (e.g, `NSUserDefaults`) and so
+//! this type exists to wrap those unsafe operations.
+
+use std::ffi::CStr;
+use std::os::raw::c_char;
+
+use objc::{class, msg_send, sel, sel_impl};
+use objc::runtime::Object;
+use objc_id::Id;
+
+use crate::foundation::{id, BOOL, YES, NO, NSInteger};
+
+/// Wrapper for a retained `NSNumber` object.
+#[derive(Debug)]
+pub struct NSNumber(pub Id<Object>);
+
+impl NSNumber {
+    pub fn bool(value: bool) -> Self {
+        NSNumber(unsafe {
+            Id::from_ptr(msg_send![class!(NSNumber), numberWithBool:match value {
+                true => YES,
+                false => NO,
+                _ => unreachable!()
+            }])
+        })
+    }
+
+    pub fn integer(value: i64) -> Self {
+        NSNumber(unsafe {
+            Id::from_ptr(msg_send![class!(NSNumber), numberWithInteger:value as NSInteger])
+        })
+    }
+
+    pub fn float(value: f64) -> Self {
+        NSNumber(unsafe {
+            Id::from_ptr(msg_send![class!(NSNumber), numberWithDouble:value])
+        })
+    }
+
+    pub fn objc_type(&self) -> &str {
+        unsafe {
+            let t: *const c_char = msg_send![&*self.0, objCType];
+            let slice = CStr::from_ptr(t);
+            slice.to_str().unwrap()
+        }
+    }
+
+    pub fn as_i64(&self) -> i64 {
+        unsafe {
+            let i: NSInteger = msg_send![&*self.0, integerValue];
+            i as i64
+        }
+    }
+
+    pub fn as_f64(&self) -> f64 {
+        unsafe {
+            msg_send![&*self.0, doubleValue]
+        }
+    }
+
+    /// If we're vended an NSNumber from a method (e.g, `NSUserDefaults` querying) we might want to
+    /// wrap it while we figure out what to do with it. This does that.
+    pub fn wrap(data: id) -> Self {
+        NSNumber(unsafe {
+            Id::from_ptr(data)
+        })
+    }
+
+    /// A helper method for determining if a given `NSObject` is an `NSNumber`.
+    pub fn is(obj: id) -> bool {
+        let result: BOOL = unsafe {
+            msg_send![obj, isKindOfClass:class!(NSNumber)]
+        };
+
+        match result {
+            YES => true,
+            NO => false,
+            _ => unreachable!()
+        }
+    }
+    
+    /// Consumes and returns the underlying `NSNumber`.
+    pub fn into_inner(mut self) -> id {
+        &mut *self.0
+    }
+}
diff --git a/src/foundation/string.rs b/src/foundation/string.rs
index f647ec7..24d9459 100644
--- a/src/foundation/string.rs
+++ b/src/foundation/string.rs
@@ -13,7 +13,7 @@ use objc::{class, msg_send, sel, sel_impl};
 use objc::runtime::Object;
 use objc_id::Id;
 
-use crate::foundation::id;
+use crate::foundation::{id, BOOL, YES, NO};
 
 const UTF8_ENCODING: usize = 4;
 
@@ -36,6 +36,16 @@ impl NSString {
         })
     }
 
+    pub fn is(obj: id) -> bool {
+        let result: BOOL = unsafe { msg_send![obj, isKindOfClass:class!(NSString)] };
+
+        match result {
+            YES => true,
+            NO => false,
+            _ => unreachable!()
+        }
+    }
+
     pub fn into_inner(mut self) -> id {
         &mut *self.0
     }
diff --git a/src/lib.rs b/src/lib.rs
index 3bc93c8..2956e15 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -24,9 +24,9 @@
 //!
 //! # Hello World
 //!
-//! ```rust,no_run
-//! use cacao::app::{App, AppDelegate};
-//! use cacao::window::Window;
+//! ```rust
+//! use cacao::macos::app::{App, AppDelegate};
+//! use cacao::macos::window::Window;
 //! 
 //! #[derive(Default)]
 //! struct BasicApp {
diff --git a/src/notification_center/mod.rs b/src/notification_center/mod.rs
index ea098ea..822ea41 100644
--- a/src/notification_center/mod.rs
+++ b/src/notification_center/mod.rs
@@ -11,9 +11,6 @@
 //! integrating with certain aspects of the underlying Cocoa/Foundation/Kit frameworks.
 //!
 //! ## Example
-//! ```rust,no_run
-//!
-//! ```
 
 use objc::{class, msg_send, sel, sel_impl};
 use objc::runtime::Object;