diff --git a/JSONAPI.playground/Pages/Full Client & Server Example.xcplaygroundpage/Contents.swift b/JSONAPI.playground/Pages/Full Client & Server Example.xcplaygroundpage/Contents.swift
index 7a83541..f7b8052 100644
--- a/JSONAPI.playground/Pages/Full Client & Server Example.xcplaygroundpage/Contents.swift	
+++ b/JSONAPI.playground/Pages/Full Client & Server Example.xcplaygroundpage/Contents.swift	
@@ -86,7 +86,7 @@ typealias SingleArticleDocument = Document<SingleResourceBody<Article>, NoInclud
 func articleDocument(includeAuthor: Bool) -> Either<SingleArticleDocument, SingleArticleDocumentWithIncludes> {
     // Let's pretend all of this is coming from a database:
 
-    let authorId = Author.ID(rawValue: "1234")
+    let authorId = Author.Id(rawValue: "1234")
 
     let article = Article(id: .init(rawValue: "5678"),
                           attributes: .init(title: .init(value: "JSON:API in Swift"),
diff --git a/JSONAPI.playground/Pages/Full Document Verbose Generation.xcplaygroundpage/Contents.swift b/JSONAPI.playground/Pages/Full Document Verbose Generation.xcplaygroundpage/Contents.swift
index 2628c38..678296e 100644
--- a/JSONAPI.playground/Pages/Full Document Verbose Generation.xcplaygroundpage/Contents.swift	
+++ b/JSONAPI.playground/Pages/Full Document Verbose Generation.xcplaygroundpage/Contents.swift	
@@ -129,9 +129,9 @@ enum ArticleDocumentError: String, JSONAPIError, Codable {
 typealias SingleArticleDocument = JSONAPI.Document<SingleResourceBody<Article>, DocumentMetadata, SingleArticleDocumentLinks, Include1<Author>, APIDescription<APIDescriptionMetadata>, ArticleDocumentError>
 
 // MARK: - Instantiations
-let authorId1 = Author.ID()
-let authorId2 = Author.ID()
-let authorId3 = Author.ID()
+let authorId1 = Author.Id()
+let authorId2 = Author.Id()
+let authorId3 = Author.Id()
 
 let now = Date()
 let tomorrow = Calendar.current.date(byAdding: .day, value: 1, to: now)!
@@ -155,7 +155,7 @@ let author1Links = EntityLinks(selfLink: .init(url: URL(string: "https://article
 											   meta: .init(expiry: tomorrow)))
 let author1 = Author(id: authorId1,
 					 attributes: .init(name: .init(value: "James Kinney")),
-					 relationships: .init(articles: .init(ids: [article.id, Article.ID(), Article.ID()],
+					 relationships: .init(articles: .init(ids: [article.id, Article.Id(), Article.Id()],
 														  meta: .init(pagination: .init(total: 3,
 																						limit: 50,
 																						offset: 0)),
@@ -167,7 +167,7 @@ let author2Links = EntityLinks(selfLink: .init(url: URL(string: "https://article
 											   meta: .init(expiry: tomorrow)))
 let author2 = Author(id: authorId2,
 					 attributes: .init(name: .init(value: "James Kinney")),
-					 relationships: .init(articles: .init(ids: [article.id, Article.ID()],
+					 relationships: .init(articles: .init(ids: [article.id, Article.Id()],
 														  meta: .init(pagination: .init(total: 2,
 																						limit: 50,
 																						offset: 0)),
diff --git a/JSONAPI.playground/Pages/Usage.xcplaygroundpage/Contents.swift b/JSONAPI.playground/Pages/Usage.xcplaygroundpage/Contents.swift
index 48296f0..1d3da07 100644
--- a/JSONAPI.playground/Pages/Usage.xcplaygroundpage/Contents.swift
+++ b/JSONAPI.playground/Pages/Usage.xcplaygroundpage/Contents.swift
@@ -20,18 +20,18 @@ let singleDogData = try! JSONEncoder().encode(singleDogDocument)
 // MARK: - Parse a request or response body with one Dog in it
 let dogResponse = try! JSONDecoder().decode(SingleDogDocument.self, from: singleDogData)
 let dogFromData = dogResponse.body.primaryResource?.value
-let dogOwner: Person.ID? = dogFromData.flatMap { $0 ~> \.owner }
+let dogOwner: Person.Id? = dogFromData.flatMap { $0 ~> \.owner }
 
 
 // MARK: - Parse a request or response body with one Dog in it using an alternative model
 typealias AltSingleDogDocument = JSONAPI.Document<SingleResourceBody<AlternativeDog>, NoMetadata, NoLinks, NoIncludes, NoAPIDescription, BasicJSONAPIError<String>>
 let altDogResponse = try! JSONDecoder().decode(AltSingleDogDocument.self, from: singleDogData)
 let altDogFromData = altDogResponse.body.primaryResource?.value
-let altDogHuman: Person.ID? = altDogFromData.flatMap { $0 ~> \.human }
+let altDogHuman: Person.Id? = altDogFromData.flatMap { $0 ~> \.human }
 
 
 // MARK: - Create a request or response with multiple people and dogs and houses included
-let personIds = [Person.ID(), Person.ID()]
+let personIds = [Person.Id(), Person.Id()]
 let dogs = try! [Dog(name: "Buddy", owner: personIds[0]), Dog(name: "Joy", owner: personIds[0]), Dog(name: "Travis", owner: personIds[1])]
 let houses = [House(attributes: .none, relationships: .none, meta: .none, links: .none), House(attributes: .none, relationships: .none, meta: .none, links: .none)]
 let people = try! [Person(id: personIds[0], name: ["Gary", "Doe"], favoriteColor: "Orange-Red", friends: [], dogs: [dogs[0], dogs[1]], home: houses[0]), Person(id: personIds[1], name: ["Elise", "Joy"], favoriteColor: "Red", friends: [], dogs: [dogs[2]], home: houses[1])]
diff --git a/JSONAPI.playground/Sources/Entities.swift b/JSONAPI.playground/Sources/Entities.swift
index 8b1564a..e64cfbb 100644
--- a/JSONAPI.playground/Sources/Entities.swift
+++ b/JSONAPI.playground/Sources/Entities.swift
@@ -63,8 +63,8 @@ public enum PersonDescription: ResourceObjectDescription {
 public typealias Person = ExampleEntity<PersonDescription>
 
 public extension ResourceObject where Description == PersonDescription, MetaType == NoMetadata, LinksType == NoLinks, EntityRawIdType == String {
-	init(id: Person.ID? = nil,name: [String], favoriteColor: String, friends: [Person], dogs: [Dog], home: House) throws {
-		self = Person(id: id ?? Person.ID(), attributes: .init(name: .init(value: name), favoriteColor: .init(value: favoriteColor)), relationships: .init(friends: .init(resourceObjects: friends), dogs: .init(resourceObjects: dogs), home: .init(resourceObject: home)), meta: .none, links: .none)
+	init(id: Person.Id? = nil,name: [String], favoriteColor: String, friends: [Person], dogs: [Dog], home: House) throws {
+		self = Person(id: id ?? Person.Id(), attributes: .init(name: .init(value: name), favoriteColor: .init(value: favoriteColor)), relationships: .init(friends: .init(resourceObjects: friends), dogs: .init(resourceObjects: dogs), home: .init(resourceObject: home)), meta: .none, links: .none)
 	}
 }
 
@@ -147,7 +147,7 @@ public extension ResourceObject where Description == DogDescription, MetaType ==
 		self = Dog(attributes: .init(name: .init(value: name)), relationships: DogDescription.Relationships(owner: .init(resourceObject: owner)), meta: .none, links: .none)
 	}
 
-	init(name: String, owner: Person.ID) throws {
+	init(name: String, owner: Person.Id) throws {
 		self = Dog(attributes: .init(name: .init(value: name)), relationships: .init(owner: .init(id: owner)), meta: .none, links: .none)
 	}
 }
diff --git a/README.md b/README.md
index e735354..22ebb8f 100644
--- a/README.md
+++ b/README.md
@@ -151,7 +151,7 @@ extension String: CreatableRawIdType {
 
 // Create a typealias because we do not expect JSON:API Resource
 // Objects for this particular API to have Metadata or Links associated
-// with them. We also expect them to have String Identifiers.
+// with them. We also expect them to have String Ids.
 typealias JSONEntity<Description: ResourceObjectDescription> = JSONAPI.ResourceObject<Description, NoMetadata, NoLinks, String>
 
 // Similarly, create a typealias for unidentified entities. JSON:API
@@ -220,7 +220,7 @@ typealias SingleArticleDocument = Document<SingleResourceBody<Article>, NoInclud
 func articleDocument(includeAuthor: Bool) -> Either<SingleArticleDocument, SingleArticleDocumentWithIncludes> {
     // Let's pretend all of this is coming from a database:
 
-    let authorId = Author.ID(rawValue: "1234")
+    let authorId = Author.Id(rawValue: "1234")
 
     let article = Article(id: .init(rawValue: "5678"),
                           attributes: .init(title: .init(value: "JSON:API in Swift"),
diff --git a/Sources/JSONAPI/Resource/Relationship.swift b/Sources/JSONAPI/Resource/Relationship.swift
index 0ab0dbf..88b54d5 100644
--- a/Sources/JSONAPI/Resource/Relationship.swift
+++ b/Sources/JSONAPI/Resource/Relationship.swift
@@ -56,25 +56,25 @@ extension ToOneRelationship where MetaType == NoMetadata, LinksType == NoLinks {
 }
 
 extension ToOneRelationship {
-    public init<T: ResourceObjectType>(resourceObject: T, meta: MetaType, links: LinksType) where T.ID == Identifiable.ID {
+    public init<T: ResourceObjectType>(resourceObject: T, meta: MetaType, links: LinksType) where T.Id == Identifiable.ID {
         self.init(id: resourceObject.id, meta: meta, links: links)
     }
 }
 
 extension ToOneRelationship where MetaType == NoMetadata, LinksType == NoLinks {
-    public init<T: ResourceObjectType>(resourceObject: T) where T.ID == Identifiable.ID {
+    public init<T: ResourceObjectType>(resourceObject: T) where T.Id == Identifiable.ID {
         self.init(id: resourceObject.id, meta: .none, links: .none)
     }
 }
 
 extension ToOneRelationship where Identifiable: OptionalRelatable {
-    public init<T: ResourceObjectType>(resourceObject: T?, meta: MetaType, links: LinksType) where T.ID == Identifiable.Wrapped.ID {
+    public init<T: ResourceObjectType>(resourceObject: T?, meta: MetaType, links: LinksType) where T.Id == Identifiable.Wrapped.ID {
         self.init(id: resourceObject?.id, meta: meta, links: links)
     }
 }
 
 extension ToOneRelationship where Identifiable: OptionalRelatable, MetaType == NoMetadata, LinksType == NoLinks {
-    public init<T: ResourceObjectType>(resourceObject: T?) where T.ID == Identifiable.Wrapped.ID {
+    public init<T: ResourceObjectType>(resourceObject: T?) where T.Id == Identifiable.Wrapped.ID {
         self.init(id: resourceObject?.id, meta: .none, links: .none)
     }
 }
@@ -96,13 +96,13 @@ public struct ToManyRelationship<Relatable: JSONAPI.Relatable, MetaType: JSONAPI
         self.links = links
     }
 
-    public init<T: JSONAPI.JSONAPIIdentifiable>(pointers: [ToOneRelationship<T, NoMetadata, NoLinks>], meta: MetaType, links: LinksType) where T.ID == Relatable.ID {
+    public init<T: JSONAPIIdentifiable>(pointers: [ToOneRelationship<T, NoMetadata, NoLinks>], meta: MetaType, links: LinksType) where T.ID == Relatable.ID {
         ids = pointers.map(\.id)
         self.meta = meta
         self.links = links
     }
 
-    public init<T: ResourceObjectType>(resourceObjects: [T], meta: MetaType, links: LinksType) where T.ID == Relatable.ID {
+    public init<T: ResourceObjectType>(resourceObjects: [T], meta: MetaType, links: LinksType) where T.Id == Relatable.ID {
         self.init(ids: resourceObjects.map(\.id), meta: meta, links: links)
     }
 
@@ -121,7 +121,7 @@ extension ToManyRelationship where MetaType == NoMetadata, LinksType == NoLinks
         self.init(ids: ids, meta: .none, links: .none)
     }
 
-    public init<T: JSONAPI.JSONAPIIdentifiable>(pointers: [ToOneRelationship<T, NoMetadata, NoLinks>]) where T.ID == Relatable.ID {
+    public init<T: JSONAPIIdentifiable>(pointers: [ToOneRelationship<T, NoMetadata, NoLinks>]) where T.ID == Relatable.ID {
         self.init(pointers: pointers, meta: .none, links: .none)
     }
 
@@ -129,7 +129,7 @@ extension ToManyRelationship where MetaType == NoMetadata, LinksType == NoLinks
         return .none(withMeta: .none, links: .none)
     }
 
-    public init<T: ResourceObjectType>(resourceObjects: [T]) where T.ID == Relatable.ID {
+    public init<T: ResourceObjectType>(resourceObjects: [T]) where T.Id == Relatable.ID {
         self.init(resourceObjects: resourceObjects, meta: .none, links: .none)
     }
 }
diff --git a/Sources/JSONAPI/Resource/Resource Object/ResourceObject.swift b/Sources/JSONAPI/Resource/Resource Object/ResourceObject.swift
index 88ae539..9ac95d8 100644
--- a/Sources/JSONAPI/Resource/Resource Object/ResourceObject.swift	
+++ b/Sources/JSONAPI/Resource/Resource Object/ResourceObject.swift	
@@ -73,6 +73,8 @@ public protocol ResourceObjectProxy: Equatable, JSONTyped {
     associatedtype Description: ResourceObjectProxyDescription
     associatedtype EntityRawIdType: JSONAPI.MaybeRawId
 
+    typealias Id = JSONAPI.Id<EntityRawIdType, Self>
+
     typealias Attributes = Description.Attributes
     typealias Relationships = Description.Relationships
 
@@ -80,7 +82,7 @@ public protocol ResourceObjectProxy: Equatable, JSONTyped {
     /// the entity is being created clientside and the
     /// server is being asked to create a unique Id. Otherwise,
     /// this should be of a type conforming to `IdType`.
-    var id: JSONAPI.Id<EntityRawIdType, Self> { get }
+    var id: Id { get }
 
     /// The JSON API compliant attributes of this `Entity`.
     var attributes: Attributes { get }
@@ -89,10 +91,6 @@ public protocol ResourceObjectProxy: Equatable, JSONTyped {
     var relationships: Relationships { get }
 }
 
-extension ResourceObjectProxy {
-    public typealias ID = JSONAPI.Id<EntityRawIdType, Self>
-}
-
 extension ResourceObjectProxy {
     /// The JSON API compliant "type" of this `ResourceObject`.
     public static var jsonType: String { return Description.jsonType }
@@ -130,7 +128,7 @@ public struct ResourceObject<Description: JSONAPI.ResourceObjectDescription, Met
     /// the entity is being created clientside and the
     /// server is being asked to create a unique Id. Otherwise,
     /// this should be of a type conforming to `IdType`.
-    public let id: ID
+    public let id: ResourceObject.Id
 
     /// The JSON API compliant attributes of this `ResourceObject`.
     public let attributes: Description.Attributes
@@ -144,7 +142,7 @@ public struct ResourceObject<Description: JSONAPI.ResourceObjectDescription, Met
     /// Links related to the entity.
     public let links: LinksType
 
-    public init(id: ID, attributes: Description.Attributes, relationships: Description.Relationships, meta: MetaType, links: LinksType) {
+    public init(id: ResourceObject.Id, attributes: Description.Attributes, relationships: Description.Relationships, meta: MetaType, links: LinksType) {
         self.id = id
         self.attributes = attributes
         self.relationships = relationships
@@ -165,7 +163,9 @@ extension ResourceObject: Hashable where EntityRawIdType: RawIdType {
     }
 }
 
-extension ResourceObject: JSONAPIIdentifiable, IdentifiableResourceObjectType, Relatable where EntityRawIdType: JSONAPI.RawIdType {}
+extension ResourceObject: JSONAPIIdentifiable, IdentifiableResourceObjectType, Relatable where EntityRawIdType: JSONAPI.RawIdType {
+    public typealias ID = ResourceObject.Id
+}
 
 @available(OSX 10.15, iOS 13, tvOS 13, watchOS 6, *)
 extension ResourceObject: Swift.Identifiable where EntityRawIdType: JSONAPI.RawIdType {}
@@ -179,7 +179,7 @@ extension ResourceObject: CustomStringConvertible {
 // MARK: - Convenience initializers
 extension ResourceObject where EntityRawIdType: CreatableRawIdType {
     public init(attributes: Description.Attributes, relationships: Description.Relationships, meta: MetaType, links: LinksType) {
-        self.id = ResourceObject.ID()
+        self.id = ResourceObject.Id()
         self.attributes = attributes
         self.relationships = relationships
         self.meta = meta
@@ -410,7 +410,7 @@ public extension ResourceObject {
         }
 
         let maybeUnidentified = Unidentified() as? EntityRawIdType
-        id = try maybeUnidentified.map { ResourceObject.ID(rawValue: $0) } ?? container.decode(ResourceObject.ID.self, forKey: .id)
+        id = try maybeUnidentified.map { ResourceObject.Id(rawValue: $0) } ?? container.decode(ResourceObject.Id.self, forKey: .id)
 
         do {
             attributes = try (NoAttributes() as? Description.Attributes)
diff --git a/Tests/JSONAPITests/Document/DocumentCompoundResourceTests.swift b/Tests/JSONAPITests/Document/DocumentCompoundResourceTests.swift
index 9980328..f42bff3 100644
--- a/Tests/JSONAPITests/Document/DocumentCompoundResourceTests.swift
+++ b/Tests/JSONAPITests/Document/DocumentCompoundResourceTests.swift
@@ -114,9 +114,9 @@ final class DocumentCompoundResourceTests: XCTestCase {
         )
 
         let ids = [
-            DocumentTests.Book.ID(),
-            DocumentTests.Book.ID(),
-            DocumentTests.Book.ID()
+            DocumentTests.Book.Id(),
+            DocumentTests.Book.Id(),
+            DocumentTests.Book.Id()
         ]
 
         let book = DocumentTests.Book(
diff --git a/Tests/JSONAPITests/Poly/PolyProxyTests.swift b/Tests/JSONAPITests/Poly/PolyProxyTests.swift
index 0cb6846..e58148d 100644
--- a/Tests/JSONAPITests/Poly/PolyProxyTests.swift
+++ b/Tests/JSONAPITests/Poly/PolyProxyTests.swift
@@ -111,9 +111,9 @@ extension Poly2: ResourceObjectProxy, JSONTyped where A == PolyProxyTests.UserA,
 	public var id: Id<EntityRawIdType, PolyProxyTests.User> {
 		switch self {
 		case .a(let a):
-			return ID(rawValue: a.id.rawValue)
+			return Id(rawValue: a.id.rawValue)
 		case .b(let b):
-			return ID(rawValue: b.id.rawValue)
+			return Id(rawValue: b.id.rawValue)
 		}
 	}
 
diff --git a/Tests/JSONAPITests/ResourceObject/ResourceObjectTests.swift b/Tests/JSONAPITests/ResourceObject/ResourceObjectTests.swift
index bf4b6be..b7b6dca 100644
--- a/Tests/JSONAPITests/ResourceObject/ResourceObjectTests.swift
+++ b/Tests/JSONAPITests/ResourceObject/ResourceObjectTests.swift
@@ -92,8 +92,8 @@ class ResourceObjectTests: XCTestCase {
 		let _ = TestEntity9(id: .init(rawValue: "9"), attributes: .none, relationships: .init(meta: .init(meta: .init(x: "hello", y: 5), links: .none), optionalMeta: nil, one: entity1.pointer, nullableOne: nil, optionalOne: nil, optionalNullableOne: .init(resourceObject: entity1, meta: .none, links: .none), optionalMany: nil), meta: .none, links: .none)
 		let _ = TestEntity9(id: .init(rawValue: "9"), attributes: .none, relationships: .init(meta: .init(meta: .init(x: "hello", y: 5), links: .none), optionalMeta: nil, one: entity1.pointer, nullableOne: nil, optionalOne: nil, optionalNullableOne: .init(resourceObject: entity1, meta: .none, links: .none), optionalMany: .init(resourceObjects: [], meta: .none, links: .none)), meta: .none, links: .none)
 		let e10id1 = TestEntity10.ID(rawValue: "hello")
-		let e10id2 = TestEntity10.ID(rawValue: "world")
-		let e10id3: TestEntity10.ID = "!"
+		let e10id2 = TestEntity10.Id(rawValue: "world")
+		let e10id3: TestEntity10.Id = "!"
 		let _ = TestEntity10(id: .init(rawValue: "10"), attributes: .none, relationships: .init(selfRef: .init(id: e10id1), selfRefs: .init(ids: [e10id2, e10id3])), meta: .none, links: .none)
 		XCTAssertNoThrow(try TestEntity11(id: .init(rawValue: "11"), attributes: .init(number: .init(rawValue: 11)), relationships: .none, meta: .none, links: .none))
 		let _ = UnidentifiedTestEntity(attributes: .init(me: .init(value: "hello")), relationships: .none, meta: .none, links: .none)
diff --git a/Tests/JSONAPITests/SwiftIdentifiableTests.swift b/Tests/JSONAPITests/SwiftIdentifiableTests.swift
index d5de133..70f6738 100644
--- a/Tests/JSONAPITests/SwiftIdentifiableTests.swift
+++ b/Tests/JSONAPITests/SwiftIdentifiableTests.swift
@@ -25,6 +25,19 @@ final class SwiftIdentifiableTests: XCTestCase {
         XCTAssertEqual(hash[t1.id], String(describing: t1.id))
         XCTAssertEqual(hash[t2.id], String(describing: t2.id))
     }
+
+    func test_Id_ID_equivalence() {
+        // it's not at all great to have both of these names for
+        // the Id type, but I could not do better than this and
+        // still have a typealias for the Id type on the
+        // ResourceObjectProxy protocol. One protocol's typealias
+        // will collide with anotehr protocol's associatedtype in
+        // very ugly ways.
+
+        XCTAssert(TestType.ID.self == TestType.Id.self)
+
+        XCTAssertEqual(TestType.ID(rawValue: "hello"), TestType.Id(rawValue: "hello"))
+    }
 }
 
 fileprivate enum TestDescription: JSONAPI.ResourceObjectDescription {
diff --git a/documentation/usage.md b/documentation/usage.md
index 7c11597..f138cac 100644
--- a/documentation/usage.md
+++ b/documentation/usage.md
@@ -167,7 +167,7 @@ typealias Relationships = NoRelationships
 
 `Relationship` values boil down to `Ids` of other resource objects. To access the `Id` of a related `ResourceObject`, you can use the custom `~>` operator with the `KeyPath` of the `Relationship` from which you want the `Id`. The friends of the above `Person` `ResourceObject` can be accessed as follows (type annotations for clarity):
 ```swift
-let friendIds: [Person.ID] = person ~> \.friends
+let friendIds: [Person.Id] = person ~> \.friends
 ```
 
 ### `JSONAPI.Attributes`
@@ -244,8 +244,8 @@ If your computed property is wrapped in a `AttributeType` then you can still use
 
 ### Copying/Mutating `ResourceObjects`
 `ResourceObject` is a value type, so copying is its default behavior. There are three common mutations you might want to make when copying a `ResourceObject`:
-1. Assigning a new `ID` to the copy of an identified `ResourceObject`.
-2. Assigning a new `ID` to the copy of an unidentified `ResourceObject`.
+1. Assigning a new `Id` to the copy of an identified `ResourceObject`.
+2. Assigning a new `Id` to the copy of an unidentified `ResourceObject`.
 3. Change attribute or relationship values.
 
 The first two can be accomplished with code like the following:
@@ -595,9 +595,9 @@ enum UserDescription: ResourceObjectDescription {
 	}
 
 	struct Relationships: JSONAPI.Relationships {
-		public var friend: (User) -> User.ID {
+		public var friend: (User) -> User.Id {
 			return { user in
-				return User.ID(rawValue: user.friend_id)
+				return User.Id(rawValue: user.friend_id)
 			}
 		}
 	}
@@ -612,4 +612,4 @@ Given a value `user` of the above resource object type, you can access the `frie
 let friendId = user ~> \.friend
 ```
 
-This works because `friend` is defined in the form: `var {name}: ({ResourceObject}) -> {ID}` where `{ResourceObject}` is the `JSONAPI.ResourceObject` described by the `ResourceObjectDescription` containing the meta-relationship.
+This works because `friend` is defined in the form: `var {name}: ({ResourceObject}) -> {Id}` where `{ResourceObject}` is the `JSONAPI.ResourceObject` described by the `ResourceObjectDescription` containing the meta-relationship.