diff --git a/lib/utopia/project/base.rb b/lib/utopia/project/base.rb
index 67aae4b..e1e3a16 100644
--- a/lib/utopia/project/base.rb
+++ b/lib/utopia/project/base.rb
@@ -16,6 +16,7 @@
 require_relative "releases_document"
 
 require_relative "guides"
+require_relative "inheritance"
 require_relative "linkify"
 
 module Utopia
@@ -203,6 +204,13 @@ def link_for(definition)
 				end
 			end
 			
+			# Resolve inheritance information for the given definition.
+			# @parameter definition [Decode::Definition] The definition to inspect.
+			# @returns [Inheritance] The inheritance information.
+			def inheritance_for(definition)
+				Inheritance.new(@index, definition)
+			end
+			
 			# Get the guides collection for this project.
 			# @returns [Guides]
 			#
diff --git a/lib/utopia/project/inheritance.rb b/lib/utopia/project/inheritance.rb
new file mode 100644
index 0000000..915dc3f
--- /dev/null
+++ b/lib/utopia/project/inheritance.rb
@@ -0,0 +1,186 @@
+# frozen_string_literal: true
+
+# Released under the MIT License.
+# Copyright, 2026, by Samuel Williams.
+
+module Utopia
+	module Project
+		# Resolves relationships and inherited methods for a definition.
+		class Inheritance
+			# A relationship declared by a definition.
+			Relationship = Struct.new(:kind, :name, :definition)
+			
+			# A method inherited from another definition.
+			Method = Struct.new(:name, :definition)
+			
+			# A group of inherited methods with the same origin.
+			Group = Struct.new(:definition, :methods)
+			
+			# Initialize inheritance resolution for the given definition.
+			# @parameter index [Decode::Index] The index used to resolve relationships.
+			# @parameter definition [Decode::Definition] The definition to inspect.
+			def initialize(index, definition)
+				@index = index
+				@definition = definition
+			end
+			
+			# The definition being inspected.
+			# @attribute [Decode::Definition]
+			attr :definition
+			
+			# Enumerate the directly declared relationships.
+			# @returns [Array(Relationship)] The relationships in declaration order.
+			def relationships
+				@relationships ||= begin
+					relationships = []
+					
+					if @definition.respond_to?(:super_class) && (name = @definition.super_class)
+						relationships << relationship(:super_class, name)
+					end
+					
+					{
+						prepends: :prepend,
+						includes: :include,
+						extends: :extend,
+					}.each do |attribute, kind|
+						if @definition.respond_to?(attribute)
+							@definition.public_send(attribute).each do |name|
+								relationships << relationship(kind, name)
+							end
+						end
+					end
+					
+					relationships
+				end
+			end
+			
+			# Enumerate documented public and protected methods inherited by the definition.
+			# @returns [Array(Group)] Methods grouped by the definition which provides them.
+			def inherited_methods
+				@groups = []
+				@groups_by_definition = {}
+				
+				collect_instance_methods(@definition, false, {}, {})
+				collect_class_methods(@definition, false, {}, {})
+				
+				return @groups
+			end
+			
+			private
+			
+			def relationship(kind, name)
+				Relationship.new(kind, name, resolve(name, @definition))
+			end
+			
+			def resolve(name, relative_to)
+				reference = relative_to.language.reference_for(name)
+				@index.lookup(reference, relative_to: relative_to)
+			end
+			
+			def relationship_definitions(definition, attribute)
+				return [] unless definition.respond_to?(attribute)
+				
+				definition.public_send(attribute).filter_map do |name|
+					resolve(name, definition)
+				end
+			end
+			
+			def super_class_for(definition)
+				if definition.respond_to?(:super_class) && (name = definition.super_class)
+					resolve(name, definition)
+				end
+			end
+			
+			def methods_for(definition, prefix)
+				return [] unless node = @index.trie.lookup(definition.full_path)
+				
+				methods = node.children.values.flat_map do |child|
+					child.values || []
+				end.select do |child|
+					child.nested_name.start_with?(prefix)
+				end
+				
+				methods.group_by(&:nested_name).map do |name, definitions|
+					definitions.find(&:documented?) || definitions.first
+				end
+			end
+			
+			def singleton_for(definition)
+				if node = @index.trie.lookup(definition.full_path)
+					if singleton = node.children[:self]
+						return singleton.values&.first
+					end
+				end
+			end
+			
+			def collect_instance_methods(definition, include_own, seen, visited, display_prefix = "#")
+				key = [definition.qualified_name, display_prefix]
+				return if visited[key]
+				visited[key] = true
+				
+				relationship_definitions(definition, :prepends).reverse_each do |relationship|
+					collect_instance_methods(relationship, true, seen, visited, display_prefix)
+				end
+				
+				collect_methods(definition, "#", display_prefix, include_own, seen)
+				
+				relationship_definitions(definition, :includes).reverse_each do |relationship|
+					collect_instance_methods(relationship, true, seen, visited, display_prefix)
+				end
+				
+				if display_prefix == "#" && (super_class = super_class_for(definition))
+					collect_instance_methods(super_class, true, seen, visited, display_prefix)
+				end
+			end
+			
+			def collect_class_methods(definition, include_own, seen, visited)
+				key = definition.qualified_name
+				return if visited[key]
+				visited[key] = true
+				
+				collect_methods(definition, ".", ".", include_own, seen)
+				if singleton = singleton_for(definition)
+					collect_methods(singleton, "#", ".", include_own, seen, definition)
+				end
+				
+				relationship_definitions(definition, :extends).reverse_each do |relationship|
+					collect_instance_methods(relationship, true, seen, {}, ".")
+				end
+				
+				if super_class = super_class_for(definition)
+					collect_class_methods(super_class, true, seen, visited)
+				end
+			end
+			
+			def collect_methods(definition, source_prefix, display_prefix, include_own, seen, origin = definition)
+				methods_for(definition, source_prefix).each do |method|
+					name = "#{display_prefix}#{method.name}"
+					next if seen[name]
+					seen[name] = true
+					
+					# Constructors are invoked through `.new` and are not useful as
+					# inherited methods.
+					if source_prefix == "#" && method.name == :initialize
+						next
+					end
+					
+					next unless include_own
+					next unless method.documented?
+					next if method.respond_to?(:private?) && method.private?
+					
+					add_method(origin, name, method)
+				end
+			end
+			
+			def add_method(definition, name, method)
+				group = @groups_by_definition[definition.qualified_name] ||= begin
+					group = Group.new(definition, [])
+					@groups << group
+					group
+				end
+				
+				group.methods << Method.new(name, method)
+			end
+		end
+	end
+end
diff --git a/pages/reference/_relationships.xnode b/pages/reference/_relationships.xnode
new file mode 100644
index 0000000..685e656
--- /dev/null
+++ b/pages/reference/_relationships.xnode
@@ -0,0 +1,45 @@
+<?r
+base = self[:base]
+symbol = self[:symbol]
+inheritance = base.inheritance_for(symbol)
+
+relationships = inheritance.relationships
+inherited_methods = inheritance.inherited_methods
+
+relationship_labels = {
+	super_class: "Inherits from",
+	prepend: "Prepends",
+	include: "Includes",
+	extend: "Extends",
+}
+?>
+<?r if relationships.any? ?>
+	<dl class="relationships"><?r
+		relationships.group_by(&:kind).each do |kind, entries|
+			?><dt>#{relationship_labels.fetch(kind)}</dt>
+			<dd><?r
+				entries.each_with_index do |relationship, index|
+					if index > 0
+						?>, <?r
+					end
+					
+					?>#{base.linkify(relationship.name, symbol)}<?r
+				end
+			?></dd><?r
+		end
+	?></dl>
+<?r end ?>
+
+<?r if inherited_methods.any? ?>
+	<section>
+		<h2>Inherited Methods</h2><?r
+		inherited_methods.each do |group|
+			?><p>From <a href="#{base.link_for(group.definition)}"><code>#{group.definition.qualified_name}</code></a>:</p>
+			<ul class="index"><?r
+				group.methods.each do |method|
+					?><li><a href="#{base.link_for(method.definition)}"><code>#{method.name}</code></a></li><?r
+				end
+			?></ul><?r
+		end
+	?></section>
+<?r end ?>
diff --git a/pages/reference/show.xnode b/pages/reference/show.xnode
index d72fcb9..ec71309 100644
--- a/pages/reference/show.xnode
+++ b/pages/reference/show.xnode
@@ -9,6 +9,7 @@
 	<h1>
 		#{partial 'content:declaration', symbol: symbol}
 	</h1>
+	#{partial 'content:relationships', symbol: symbol}
 	
 	<?r
 	if document = base.document_for(symbol)
diff --git a/public/_static/site.css b/public/_static/site.css
index 2396427..cc4c5cc 100644
--- a/public/_static/site.css
+++ b/public/_static/site.css
@@ -429,6 +429,18 @@ details dt, details dd {
 	margin: 1rem 0;
 }
 
+dl.relationships {
+	display: grid;
+	grid-template-columns: max-content minmax(0, 1fr);
+	align-items: baseline;
+	gap: 0.25rem 1rem;
+	margin-top: 0.5rem;
+}
+
+dl.relationships dt, dl.relationships dd {
+	margin: 0;
+}
+
 ul.index {
 	padding: 0;
 	list-style: none;
diff --git a/test/utopia/project/.fixtures/inheritance.rb b/test/utopia/project/.fixtures/inheritance.rb
new file mode 100644
index 0000000..69ca6b0
--- /dev/null
+++ b/test/utopia/project/.fixtures/inheritance.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+# Released under the MIT License.
+# Copyright, 2026, by Samuel Williams.
+
+module Example
+	module Included
+		# An included method.
+		def included_method
+		end
+		
+		# An included method which is overridden by the child.
+		def overridden_method
+		end
+		
+		private
+		
+		# A private included method.
+		def private_included_method
+		end
+	end
+	
+	module Prepended
+		# A prepended method.
+		def prepended_method
+		end
+	end
+	
+	module Extended
+		# An extended method.
+		def extended_method
+		end
+	end
+	
+	class Parent
+		# Initialize the parent.
+		def initialize
+		end
+		
+		# An inherited instance method.
+		def parent_method
+		end
+		
+		# An inherited class method.
+		def self.parent_class_method
+		end
+		
+		class << self
+			# An inherited singleton class method.
+			def singleton_class_method
+			end
+		end
+		
+		private
+		
+		# A private parent method.
+		def private_parent_method
+		end
+	end
+	
+	class Child < Parent
+		include Included
+		prepend Prepended
+		extend Extended
+		
+		# Override the included method.
+		def overridden_method
+		end
+	end
+end
diff --git a/test/utopia/project/inheritance.rb b/test/utopia/project/inheritance.rb
new file mode 100644
index 0000000..1f05964
--- /dev/null
+++ b/test/utopia/project/inheritance.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+# Released under the MIT License.
+# Copyright, 2026, by Samuel Williams.
+
+require "utopia/project/inheritance"
+
+require "decode"
+
+describe Utopia::Project::Inheritance do
+	let(:path) {File.expand_path(".fixtures/inheritance.rb", __dir__)}
+	let(:index) {Decode::Index.for(path)}
+	let(:definition) {index.definitions.fetch("Example::Child")}
+	let(:inheritance) {subject.new(index, definition)}
+	
+	it "resolves declared relationships" do
+		relationships = inheritance.relationships.to_h do |relationship|
+			[relationship.kind, relationship.definition.qualified_name]
+		end
+		
+		expect(relationships).to be == {
+			super_class: "Example::Parent",
+			prepend: "Example::Prepended",
+			include: "Example::Included",
+			extend: "Example::Extended",
+		}
+	end
+	
+	it "groups inherited methods by their origin" do
+		methods = inheritance.inherited_methods.to_h do |group|
+			[group.definition.qualified_name, group.methods.map(&:name)]
+		end
+		
+		expect(methods).to be == {
+			"Example::Prepended" => ["#prepended_method"],
+			"Example::Included" => ["#included_method"],
+			"Example::Parent" => ["#parent_method", ".parent_class_method", ".singleton_class_method"],
+			"Example::Extended" => [".extended_method"],
+		}
+	end
+end
diff --git a/test/utopia/project/serve.rb b/test/utopia/project/serve.rb
index ebf5cd0..7b70bb6 100644
--- a/test/utopia/project/serve.rb
+++ b/test/utopia/project/serve.rb
@@ -80,5 +80,8 @@
 		
 		expect(body).to be(:include?, "def release_names")
 		expect(body).to be(:include?, 'class ReleasesDocument &lt; <a href="/reference/Utopia/Project/Document/index" title="Utopia::Project::Document">Document</a>')
+		expect(body).to be(:include?, '<dl class="relationships">')
+		expect(body).to be(:include?, "<dt>Inherits from</dt>")
+		expect(body).to be(:include?, "/reference/Utopia/Project/Document/index#Utopia%3A%3AProject%3A%3ADocument%23root")
 	end
 end
diff --git a/utopia-project.gemspec b/utopia-project.gemspec
index 912f915..1bd340b 100644
--- a/utopia-project.gemspec
+++ b/utopia-project.gemspec
@@ -25,7 +25,7 @@ Gem::Specification.new do |spec|
 	
 	spec.required_ruby_version = ">= 3.3"
 	
-	spec.add_dependency "decode", "~> 0.29"
+	spec.add_dependency "decode", "~> 0.30"
 	spec.add_dependency "falcon"
 	spec.add_dependency "markly", "~> 0.15"
 	spec.add_dependency "thread-local"