diff --git a/angel_graphql/example/main.dart b/angel_graphql/example/main.dart
index d16c6dd1..c4deebb4 100644
--- a/angel_graphql/example/main.dart
+++ b/angel_graphql/example/main.dart
@@ -1,10 +1,10 @@
 import 'package:angel_framework/angel_framework.dart';
 import 'package:angel_graphql/angel_graphql.dart';
 import 'package:angel_serialize/angel_serialize.dart';
-import 'package:logging/logging.dart';
 import 'package:graphql_schema/graphql_schema.dart';
 import 'package:graphql_server/graphql_server.dart';
 import 'package:graphql_server/mirrors.dart';
+import 'package:logging/logging.dart';
 
 main() async {
   var app = new Angel();
@@ -19,7 +19,7 @@ main() async {
 
   var todoService = app.use('api/todos', new MapService()) as Service;
 
-  var api = objectType('api', [
+  var api = objectType('api', fields: [
     field(
       'todo',
       type: listType(objectTypeFromDartType(Todo)),
diff --git a/graphql_schema/example/todo.dart b/graphql_schema/example/todo.dart
index b837d612..32f0d93d 100644
--- a/graphql_schema/example/todo.dart
+++ b/graphql_schema/example/todo.dart
@@ -1,7 +1,7 @@
 import 'package:graphql_schema/graphql_schema.dart';
 
 final GraphQLSchema todoSchema = new GraphQLSchema(
-  query: objectType('Todo', [
+  query: objectType('Todo', fields: [
     field(
       'text',
       type: graphQLString.nonNullable(),
diff --git a/graphql_schema/lib/introspection.dart b/graphql_schema/lib/introspection.dart
index 5903253d..cfe1ac8a 100644
--- a/graphql_schema/lib/introspection.dart
+++ b/graphql_schema/lib/introspection.dart
@@ -1,16 +1,33 @@
 import 'package:graphql_schema/graphql_schema.dart';
 
 // TODO: How to handle custom types???
-GraphQLSchema reflectSchema(GraphQLSchema schema) {
-  var objectTypes = _fetchAllTypes(schema);
-  var typeType = _reflectSchemaTypes(schema);
+GraphQLSchema reflectSchema(GraphQLSchema schema, List<GraphQLType> allTypes) {
+  var objectTypes = fetchAllTypes(schema);
+  allTypes.addAll(objectTypes);
+  var typeType = _reflectSchemaTypes();
 
-  var schemaType = objectType('__Schema', [
+  var schemaType = objectType('__Schema', fields: [
     field(
       'types',
       type: listType(typeType),
       resolve: (_, __) => objectTypes,
     ),
+    field(
+      'queryType',
+      type: typeType,
+      resolve: (_, __) => schema.query,
+    ),
+    field(
+      'mutationType',
+      type: typeType,
+      resolve: (_, __) => schema.mutation,
+    ),
+  ]);
+
+  allTypes.addAll([
+    typeType,
+    schemaType,
+    _reflectFields(),
   ]);
 
   var fields = <GraphQLField>[
@@ -37,38 +54,109 @@ GraphQLSchema reflectSchema(GraphQLSchema schema) {
   fields.addAll(schema.query.fields);
 
   return new GraphQLSchema(
-    query: objectType(schema.query.name, fields),
+    query: objectType(schema.query.name, fields: fields),
     mutation: schema.mutation,
   );
 }
 
-GraphQLObjectType _reflectSchemaTypes(GraphQLSchema schema) {
+GraphQLObjectType _typeType;
+
+GraphQLObjectType _reflectSchemaTypes() {
+  if (_typeType == null) {
+    _typeType = _createTypeType();
+    _typeType.fields.add(
+      field(
+        'ofType',
+        type: _reflectSchemaTypes(),
+        resolve: (type, _) {
+          if (type is GraphQLListType)
+            return type.innerType;
+          else if (type is GraphQLNonNullableType) return type.innerType;
+          return null;
+        },
+      ),
+    );
+
+    var fieldType = _reflectFields();
+    var typeField = fieldType.fields
+        .firstWhere((f) => f.name == 'type', orElse: () => null);
+
+    if (typeField == null) {
+      fieldType.fields.add(
+        field(
+          'type',
+          type: _reflectSchemaTypes(),
+          resolve: (f, _) => (f as GraphQLField).type,
+        ),
+      );
+    }
+  }
+
+  return _typeType;
+}
+
+GraphQLObjectType _createTypeType() {
   var fieldType = _reflectFields();
 
-  return objectType('__Type', [
+  return objectType('__Type', fields: [
     field(
       'name',
       type: graphQLString,
-      resolve: (type, _) => (type as GraphQLObjectType).name,
+      resolve: (type, _) => (type as GraphQLType).name,
+    ),
+    field(
+      'description',
+      type: graphQLString,
+      resolve: (type, _) => (type as GraphQLType).description,
     ),
     field(
       'kind',
       type: graphQLString,
-      resolve: (type, _) => 'OBJECT', // TODO: Union, interface
+      resolve: (type, _) {
+        var t = type as GraphQLType;
+
+        if (t is GraphQLScalarType)
+          return 'SCALAR';
+        else if (t is GraphQLObjectType)
+          return 'OBJECT';
+        else if (t is GraphQLListType)
+          return 'LIST';
+        else if (t is GraphQLNonNullableType)
+          return 'NON_NULL';
+        else
+          throw new UnsupportedError(
+              'Cannot get the kind of $t.'); // TODO: Interface + union
+      },
     ),
     field(
       'fields',
       type: listType(fieldType),
-      resolve: (type, _) => (type as GraphQLObjectType).fields,
+      resolve: (type, _) => type is GraphQLObjectType ? type.fields : [],
     ),
   ]);
 }
 
+GraphQLObjectType _fieldType;
+
 GraphQLObjectType _reflectFields() {
-  return objectType('__Field', []);
+  if (_fieldType == null) {
+    _fieldType = _createFieldType();
+  }
+
+  return _fieldType;
 }
 
-List<GraphQLObjectType> _fetchAllTypes(GraphQLSchema schema) {
+GraphQLObjectType _createFieldType() {
+  return objectType('__Field', fields: [
+    field(
+      'name',
+      type: graphQLString,
+      resolve: (f, _) => (f as GraphQLField).name,
+    ),
+  ]);
+}
+
+List<GraphQLObjectType> fetchAllTypes(GraphQLSchema schema) {
   var typess = <GraphQLType>[];
   typess.addAll(_fetchAllTypesFromObject(schema.query));
 
diff --git a/graphql_schema/lib/src/gen.dart b/graphql_schema/lib/src/gen.dart
index 5b833bf2..31d6a5c3 100644
--- a/graphql_schema/lib/src/gen.dart
+++ b/graphql_schema/lib/src/gen.dart
@@ -1,8 +1,8 @@
 part of graphql_schema.src.schema;
 
 GraphQLObjectType objectType(String name,
-        [Iterable<GraphQLField> fields = const []]) =>
-    new GraphQLObjectType(name)..fields.addAll(fields ?? []);
+        {String description, Iterable<GraphQLField> fields = const []}) =>
+    new GraphQLObjectType(name, description)..fields.addAll(fields ?? []);
 
 GraphQLField<T, Serialized> field<T, Serialized>(String name,
     {Iterable<GraphQLFieldArgument<T, Serialized>> arguments: const [],
diff --git a/graphql_schema/lib/src/object_type.dart b/graphql_schema/lib/src/object_type.dart
index 8f98a72e..264f5521 100644
--- a/graphql_schema/lib/src/object_type.dart
+++ b/graphql_schema/lib/src/object_type.dart
@@ -4,9 +4,10 @@ class GraphQLObjectType
     extends GraphQLType<Map<String, dynamic>, Map<String, dynamic>>
     with _NonNullableMixin<Map<String, dynamic>, Map<String, dynamic>> {
   final String name;
+  final String description;
   final List<GraphQLField> fields = [];
 
-  GraphQLObjectType(this.name);
+  GraphQLObjectType(this.name, this.description);
 
   @override
   ValidationResult<Map<String, dynamic>> validate(String key, Map input) {
diff --git a/graphql_schema/lib/src/scalar.dart b/graphql_schema/lib/src/scalar.dart
index 21210bdf..2041d3c7 100644
--- a/graphql_schema/lib/src/scalar.dart
+++ b/graphql_schema/lib/src/scalar.dart
@@ -17,15 +17,20 @@ final GraphQLScalarType<DateTime, String> graphQLDate =
     new _GraphQLDateType._();
 
 /// A signed 32‐bit integer.
-final GraphQLScalarType<int, int> graphQLInt =
-    new _GraphQLNumType<int>((x) => x is int, 'an integer');
+final GraphQLScalarType<int, int> graphQLInt = new _GraphQLNumType<int>(
+    'Int', 'A signed 64-bit integer.', (x) => x is int, 'an integer');
 
 /// A signed double-precision floating-point value.
 final GraphQLScalarType<double, double> graphQLFloat =
-    new _GraphQLNumType<double>((x) => x is double, 'a float');
+    new _GraphQLNumType<double>(
+        'Float',
+        'A signed double-precision floating-point value.',
+        (x) => x is double,
+        'a float');
 
 abstract class GraphQLScalarType<Value, Serialized>
-    extends GraphQLType<Value, Serialized> with _NonNullableMixin<Value, Serialized> {}
+    extends GraphQLType<Value, Serialized>
+    with _NonNullableMixin<Value, Serialized> {}
 
 typedef bool _NumVerifier(x);
 
@@ -35,6 +40,12 @@ class _GraphQLBoolType extends GraphQLScalarType<bool, bool> {
     return value;
   }
 
+  @override
+  String get name => 'Boolean';
+
+  @override
+  String get description => 'A boolean value; can be either true or false.';
+
   @override
   ValidationResult<bool> validate(String key, input) {
     if (input != null && input is! bool)
@@ -50,10 +61,12 @@ class _GraphQLBoolType extends GraphQLScalarType<bool, bool> {
 }
 
 class _GraphQLNumType<T extends num> extends GraphQLScalarType<T, T> {
+  final String name;
+  final String description;
   final _NumVerifier verifier;
   final String expected;
 
-  _GraphQLNumType(this.verifier, this.expected);
+  _GraphQLNumType(this.name, this.description, this.verifier, this.expected);
 
   @override
   ValidationResult<T> validate(String key, input) {
@@ -78,6 +91,12 @@ class _GraphQLNumType<T extends num> extends GraphQLScalarType<T, T> {
 class _GraphQLStringType extends GraphQLScalarType<String, String> {
   _GraphQLStringType._();
 
+  @override
+  String get name => 'String';
+
+  @override
+  String get description => 'A character sequence.';
+
   @override
   String serialize(String value) => value;
 
@@ -95,6 +114,12 @@ class _GraphQLDateType extends GraphQLScalarType<DateTime, String>
     with _NonNullableMixin<DateTime, String> {
   _GraphQLDateType._();
 
+  @override
+  String get name => 'Date';
+
+  @override
+  String get description => 'An ISO0-8601 Date.';
+
   @override
   String serialize(DateTime value) => value.toIso8601String();
 
diff --git a/graphql_schema/lib/src/type.dart b/graphql_schema/lib/src/type.dart
index db4e092a..3944f681 100644
--- a/graphql_schema/lib/src/type.dart
+++ b/graphql_schema/lib/src/type.dart
@@ -1,9 +1,16 @@
 part of graphql_schema.src.schema;
 
 abstract class GraphQLType<Value, Serialized> {
+  String get name;
+
+  String get description;
+
   Serialized serialize(Value value);
+
   Value deserialize(Serialized serialized);
+
   ValidationResult<Serialized> validate(String key, Serialized input);
+
   GraphQLType<Value, Serialized> nonNullable();
 }
 
@@ -16,8 +23,16 @@ class GraphQLListType<Value, Serialized>
     extends GraphQLType<List<Value>, List<Serialized>>
     with _NonNullableMixin<List<Value>, List<Serialized>> {
   final GraphQLType<Value, Serialized> innerType;
+
   GraphQLListType(this.innerType);
 
+  @override
+  String get name => null;
+
+  @override
+  String get description =>
+      'A list of items of type ${innerType.name ?? '(${innerType.description}).'}';
+
   @override
   ValidationResult<List<Serialized>> validate(
       String key, List<Serialized> input) {
@@ -55,6 +70,7 @@ class GraphQLListType<Value, Serialized>
 abstract class _NonNullableMixin<Value, Serialized>
     implements GraphQLType<Value, Serialized> {
   GraphQLType<Value, Serialized> _nonNullableCache;
+
   GraphQLType<Value, Serialized> nonNullable() => _nonNullableCache ??=
       new GraphQLNonNullableType<Value, Serialized>._(this);
 }
@@ -62,8 +78,16 @@ abstract class _NonNullableMixin<Value, Serialized>
 class GraphQLNonNullableType<Value, Serialized>
     extends GraphQLType<Value, Serialized> {
   final GraphQLType<Value, Serialized> innerType;
+
   GraphQLNonNullableType._(this.innerType);
 
+  @override
+  String get name => innerType.name;
+
+  @override
+  String get description =>
+      'A non-nullable binding to ${innerType.name ?? '(${innerType.description}).'}';
+
   @override
   GraphQLType<Value, Serialized> nonNullable() {
     throw new UnsupportedError(
diff --git a/graphql_schema/test/common.dart b/graphql_schema/test/common.dart
index 5b5ae5d2..a9f9a0b4 100644
--- a/graphql_schema/test/common.dart
+++ b/graphql_schema/test/common.dart
@@ -1,14 +1,14 @@
 import 'package:graphql_schema/graphql_schema.dart';
 
-final GraphQLObjectType pokemonType = objectType('Pokemon', [
+final GraphQLObjectType pokemonType = objectType('Pokemon', fields:[
   field('species', type: graphQLString),
   field('catch_date', type: graphQLDate)
 ]);
 
 final GraphQLObjectType trainerType =
-    objectType('Trainer', [field('name', type: graphQLString)]);
+    objectType('Trainer', fields:[field('name', type: graphQLString)]);
 
-final GraphQLObjectType pokemonRegionType = objectType('PokemonRegion', [
+final GraphQLObjectType pokemonRegionType = objectType('PokemonRegion', fields:[
   field('trainer', type: trainerType),
   field('pokemon_species', type: listType(pokemonType))
 ]);
diff --git a/graphql_server/lib/graphql_server.dart b/graphql_server/lib/graphql_server.dart
index dcd4bf53..8b5f3035 100644
--- a/graphql_server/lib/graphql_server.dart
+++ b/graphql_server/lib/graphql_server.dart
@@ -10,7 +10,12 @@ class GraphQL {
 
   GraphQL(GraphQLSchema schema, {bool introspect: true}) : _schema = schema {
     if (introspect) {
-      _schema = reflectSchema(_schema);
+      var allTypes = <GraphQLType>[];
+      _schema = reflectSchema(_schema, allTypes);
+
+      for (var type in allTypes) {
+        customTypes[type.name] = type;
+      }
     }
 
     if (_schema.query != null) customTypes[_schema.query.name] = _schema.query;
diff --git a/graphql_server/lib/mirrors.dart b/graphql_server/lib/mirrors.dart
index 5eb8d60d..329a0d9d 100644
--- a/graphql_server/lib/mirrors.dart
+++ b/graphql_server/lib/mirrors.dart
@@ -23,8 +23,13 @@ GraphQLType _objectTypeFromDartType(Type type, [List<Type> typeArguments]) {
     return graphQLBoolean;
   } else if (type == int) {
     return graphQLInt;
-  } else if (type == double || type == num) {
+  } else if (type == double) {
     return graphQLFloat;
+  } else if (type == num) {
+    throw new UnsupportedError(
+        'Cannot convert `num` to a GraphQL type. Choose `int` or `float` instead.');
+  } else if (type == Null) {
+    throw new UnsupportedError('Cannot convert `Null` to a GraphQL type.');
   } else if (type == String) {
     return graphQLString;
   } else if (type == DateTime) {
@@ -57,7 +62,10 @@ GraphQLObjectType objectTypeFromClassMirror(ClassMirror mirror) {
     }
   }
 
-  return objectType(MirrorSystem.getName(mirror.simpleName), fields);
+  return objectType(
+    MirrorSystem.getName(mirror.simpleName),
+    fields: fields,
+  );
 }
 
 GraphQLField fieldFromGetter(
diff --git a/graphql_server/test/query_test.dart b/graphql_server/test/query_test.dart
index 8ca391fb..e9775dd0 100644
--- a/graphql_server/test/query_test.dart
+++ b/graphql_server/test/query_test.dart
@@ -4,7 +4,7 @@ import 'package:test/test.dart';
 
 void main() {
   test('single element', () async {
-    var todoType = objectType('todo', [
+    var todoType = objectType('todo',fields: [
       field(
         'text',
         type: graphQLString,
@@ -18,7 +18,7 @@ void main() {
     ]);
 
     var schema = graphQLSchema(
-      query: objectType('api', [
+      query: objectType('api', fields:[
         field(
           'todos',
           type: listType(todoType),