diff --git a/benchmarks/HugeSchemaBench.php b/benchmarks/HugeSchemaBench.php
index d0cce0f..7146e7f 100644
--- a/benchmarks/HugeSchemaBench.php
+++ b/benchmarks/HugeSchemaBench.php
@@ -21,11 +21,6 @@ class HugeSchemaBench
      */
     private $schemaBuilder;
 
-    /**
-     * @var \GraphQL\Type\Descriptor
-     */
-    private $descriptor;
-
     private $schema;
 
     private $lazySchema;
@@ -47,7 +42,6 @@ class HugeSchemaBench
         $this->schema = $this->schemaBuilder->buildSchema();
 
         $queryBuilder = new QueryGenerator($this->schema, 0.05);
-        $this->descriptor = $this->schema->describe();
         $this->smallQuery = $queryBuilder->buildQuery();
     }
 
@@ -80,7 +74,6 @@ class HugeSchemaBench
         return new Schema(
             \GraphQL\Type\SchemaConfig::create()
                 ->setQuery($this->schemaBuilder->buildQueryType())
-                // ->setDescriptor($this->descriptor)
                 ->setTypeLoader(function($name) {
                     return $this->schemaBuilder->loadType($name);
                 })
diff --git a/src/Executor/Executor.php b/src/Executor/Executor.php
index 0a62d78..5ac9733 100644
--- a/src/Executor/Executor.php
+++ b/src/Executor/Executor.php
@@ -1062,7 +1062,7 @@ class Executor
         $runtimeType = $returnType->resolveType($result, $exeContext->contextValue, $info);
 
         if (null === $runtimeType) {
-            if ($returnType instanceof InterfaceType && !$exeContext->schema->getConfig()->descriptor) {
+            if ($returnType instanceof InterfaceType) {
                 Warning::warnOnce(
                     "GraphQL Interface Type `{$returnType->name}` returned `null` from it`s `resolveType` function ".
                     'for value: ' . Utils::printSafe($result) . '. Switching to slow resolution method using `isTypeOf` ' .
diff --git a/src/Type/Descriptor.php b/src/Type/Descriptor.php
deleted file mode 100644
index 39e98cf..0000000
--- a/src/Type/Descriptor.php
+++ /dev/null
@@ -1,61 +0,0 @@
-<?php
-namespace GraphQL\Type;
-
-use GraphQL\Utils\Utils;
-
-class Descriptor implements \JsonSerializable
-{
-    public $version = '1.0';
-
-    public $typeMap = [];
-
-    public $possibleTypeMap = [];
-
-    public $created;
-
-    public static function fromArray(array $array)
-    {
-        Utils::invariant(
-            isset($array['version'], $array['typeMap'], $array['possibleTypeMap'], $array['created']),
-            __METHOD__ . ' expects array with keys "version", "typeMap", "possibleTypeMap", "created" but got keys: %s',
-            implode(', ', array_keys($array))
-        );
-        Utils::invariant(
-            is_string($array['version']) && '1.0' === $array['version'],
-            __METHOD__ . ' expects array where "version" key equals to "1.0"'
-        );
-        Utils::invariant(
-            is_array($array['typeMap']) && is_array($array['possibleTypeMap']),
-            __METHOD__ . ' expects array where "typeMap" and "possibleTypeMap" keys are arrays'
-        );
-        Utils::invariant(
-            is_int($array['created']),
-            __METHOD__ . ' expects array where "created" key is integer timestamp'
-        );
-
-        $descriptor = new self();
-        Utils::assign($descriptor, $array);
-    }
-
-    public function toArray()
-    {
-        return [
-            'typeMap' => $this->typeMap,
-            'version' => $this->version,
-            'possibleTypeMap' => $this->possibleTypeMap,
-            'created' => $this->created
-        ];
-    }
-
-    /**
-     * Specify data which should be serialized to JSON
-     * @link http://php.net/manual/en/jsonserializable.jsonserialize.php
-     * @return mixed data which can be serialized by <b>json_encode</b>,
-     * which is a value of any type other than a resource.
-     * @since 5.4.0
-     */
-    function jsonSerialize()
-    {
-        return $this->toArray();
-    }
-}
diff --git a/src/Type/Schema.php b/src/Type/Schema.php
index 4909e49..3623da4 100644
--- a/src/Type/Schema.php
+++ b/src/Type/Schema.php
@@ -49,13 +49,6 @@ class Schema
      */
     private $config;
 
-    /**
-     * Contains actual descriptor for this schema
-     *
-     * @var Descriptor
-     */
-    private $descriptor;
-
     /**
      * Contains currently resolved schema types
      *
@@ -63,6 +56,11 @@ class Schema
      */
     private $resolvedTypes = [];
 
+    /**
+     * @var array
+     */
+    private $possibleTypeMap;
+
     /**
      * True when $resolvedTypes contain all possible schema types
      *
@@ -104,8 +102,7 @@ class Schema
                 'subscription',
                 'types',
                 'directives',
-                'typeLoader',
-                'descriptor'
+                'typeLoader'
             ]),
             Utils::getVariableType($config)
         );
@@ -116,6 +113,15 @@ class Schema
         );
 
         $this->config = $config;
+
+        $this->resolvedTypes[$config->query->name] = $config->query;
+
+        if ($config->mutation) {
+            $this->resolvedTypes[$config->mutation->name] = $config->mutation;
+        }
+        if ($config->subscription) {
+            $this->resolvedTypes[$config->subscription->name] = $config->subscription;
+        }
     }
 
     /**
@@ -165,15 +171,7 @@ class Schema
     public function getTypeMap()
     {
         if (!$this->fullyLoaded) {
-            if ($this->config->descriptor && $this->config->typeLoader) {
-                // Following is still faster than $this->collectAllTypes() because it won't init fields
-                $typesToResolve = array_diff_key($this->config->descriptor->typeMap, $this->resolvedTypes);
-                foreach ($typesToResolve as $typeName => $_) {
-                    $this->resolvedTypes[$typeName] = $this->loadType($typeName);
-                }
-            } else {
-                $this->resolvedTypes = $this->collectAllTypes();
-            }
+            $this->resolvedTypes = $this->collectAllTypes();
             $this->fullyLoaded = true;
         }
         return $this->resolvedTypes;
@@ -190,51 +188,11 @@ class Schema
         return $this->resolveType($name);
     }
 
-    /**
-     * Returns serializable schema descriptor which can be passed later
-     * to Schema config to enable a set of performance optimizations
-     *
-     * @return Descriptor
-     */
-    public function describe()
-    {
-        if ($this->descriptor) {
-            return $this->descriptor;
-        }
-
-        $this->resolvedTypes = $this->collectAllTypes();
-        $this->fullyLoaded = true;
-
-        $descriptor = new Descriptor();
-        $descriptor->version = '1.0';
-        $descriptor->created = time();
-
-        foreach ($this->resolvedTypes as $type) {
-            if ($type instanceof ObjectType) {
-                foreach ($type->getInterfaces() as $interface) {
-                    $descriptor->possibleTypeMap[$interface->name][$type->name] = 1;
-                }
-            } else if ($type instanceof UnionType) {
-                foreach ($type->getTypes() as $innerType) {
-                    $descriptor->possibleTypeMap[$type->name][$innerType->name] = 1;
-                }
-            }
-            $descriptor->typeMap[$type->name] = 1;
-        }
-
-        return $this->descriptor = $descriptor;
-    }
-
     private function collectAllTypes()
     {
         $initialTypes = array_merge(
-            [
-                $this->config->query,
-                $this->config->mutation,
-                $this->config->subscription,
-                Introspection::_schema()
-            ],
-            array_values($this->resolvedTypes)
+            array_values($this->resolvedTypes),
+            [Introspection::_schema()]
         );
 
         $typeMap = [];
@@ -276,20 +234,30 @@ class Schema
      */
     public function getPossibleTypes(AbstractType $abstractType)
     {
-        if ($abstractType instanceof UnionType) {
-            return $abstractType->getTypes();
-        }
+        $possibleTypeMap = $this->getPossibleTypeMap();
+        return array_values($possibleTypeMap[$abstractType->name]);
+    }
 
-        /** @var InterfaceType $abstractType */
-        $descriptor = $this->config->descriptor ?: $this->describe();
-
-        $result = [];
-        if (isset($descriptor->possibleTypeMap[$abstractType->name])) {
-            foreach ($descriptor->possibleTypeMap[$abstractType->name] as $typeName => $_) {
-                $result[] = $this->resolveType($typeName);
+    /**
+     * @return array
+     */
+    private function getPossibleTypeMap()
+    {
+        if ($this->possibleTypeMap === null) {
+            $this->possibleTypeMap = [];
+            foreach ($this->getTypeMap() as $type) {
+                if ($type instanceof ObjectType) {
+                    foreach ($type->getInterfaces() as $interface) {
+                        $this->possibleTypeMap[$interface->name][$type->name] = $type;
+                    }
+                } else if ($type instanceof UnionType) {
+                    foreach ($type->getTypes() as $innerType) {
+                        $this->possibleTypeMap[$type->name][$innerType->name] = $innerType;
+                    }
+                }
             }
         }
-        return $result;
+        return $this->possibleTypeMap;
     }
 
     /**
@@ -336,10 +304,6 @@ class Schema
      */
     public function isPossibleType(AbstractType $abstractType, ObjectType $possibleType)
     {
-        if ($this->config->descriptor) {
-            return !empty($this->config->descriptor->possibleTypeMap[$abstractType->name][$possibleType->name]);
-        }
-
         if ($abstractType instanceof InterfaceType) {
             return $possibleType->implementsInterface($abstractType);
         }
@@ -381,14 +345,8 @@ class Schema
     private function defaultTypeLoader($typeName)
     {
         // Default type loader simply fallbacks to collecting all types
-        if (!$this->fullyLoaded) {
-            $this->resolvedTypes = $this->collectAllTypes();
-            $this->fullyLoaded = true;
-        }
-        if (!isset($this->resolvedTypes[$typeName])) {
-            return null;
-        }
-        return $this->resolvedTypes[$typeName];
+        $typeMap = $this->getTypeMap();
+        return isset($typeMap[$typeName]) ? $typeMap[$typeName] : null;
     }
 
 
diff --git a/src/Type/SchemaConfig.php b/src/Type/SchemaConfig.php
index 07efb3c..96e9db3 100644
--- a/src/Type/SchemaConfig.php
+++ b/src/Type/SchemaConfig.php
@@ -1,8 +1,6 @@
 <?php
 namespace GraphQL\Type;
 
-use GraphQL\Error\InvariantViolation;
-use GraphQL\Type\Descriptor;
 use GraphQL\Type\Definition\Directive;
 use GraphQL\Type\Definition\ObjectType;
 use GraphQL\Type\Definition\Type;
@@ -41,11 +39,6 @@ class SchemaConfig
      */
     public $directives;
 
-    /**
-     * @var Descriptor
-     */
-    public $descriptor;
-
     /**
      * @var callable
      */
@@ -105,6 +98,20 @@ class SchemaConfig
                 $config->setDirectives($options['directives']);
             }
 
+            if (isset($options['typeResolution'])) {
+                trigger_error(
+                    'Type resolution strategies are deprecated. Just pass single option `typeLoader` '.
+                    'to schema constructor instead.',
+                    E_USER_DEPRECATED
+                );
+                if ($options['typeResolution'] instanceof Resolution && !isset($options['typeLoader'])) {
+                    $strategy = $options['typeResolution'];
+                    $options['typeLoader'] = function($name) use ($strategy) {
+                        return $strategy->resolveType($name);
+                    };
+                }
+            }
+
             if (isset($options['typeLoader'])) {
                 Utils::invariant(
                     is_callable($options['typeLoader']),
@@ -113,15 +120,6 @@ class SchemaConfig
                 );
                 $config->setTypeLoader($options['typeLoader']);
             }
-
-            if (isset($options['descriptor'])) {
-                Utils::invariant(
-                    $options['descriptor'] instanceof Descriptor,
-                    'Schema descriptor must be instance of GraphQL\Type\Descriptor but got: %s',
-                    Utils::getVariableType($options['descriptor'])
-                );
-                $config->setDescriptor($options['descriptor']);
-            }
         }
 
         return $config;
@@ -217,24 +215,6 @@ class SchemaConfig
         return $this;
     }
 
-    /**
-     * @return Descriptor
-     */
-    public function getDescriptor()
-    {
-        return $this->descriptor;
-    }
-
-    /**
-     * @param Descriptor $descriptor
-     * @return SchemaConfig
-     */
-    public function setDescriptor(Descriptor $descriptor)
-    {
-        $this->descriptor = $descriptor;
-        return $this;
-    }
-
     /**
      * @return callable
      */
diff --git a/src/Utils/TypeInfo.php b/src/Utils/TypeInfo.php
index 4edfc00..4cc09d4 100644
--- a/src/Utils/TypeInfo.php
+++ b/src/Utils/TypeInfo.php
@@ -106,7 +106,7 @@ class TypeInfo
         }
         if (!$type instanceof Type) {
             Warning::warnOnce(
-                'One of schema types is not a valid type definition instance. Ignoring it. '.
+                'One of the schema types is not a valid type definition instance. '.
                 'Try running $schema->assertValid() to find out the cause of this warning.',
                 Warning::NOT_A_TYPE
             );
diff --git a/tests/Type/DefinitionTest.php b/tests/Type/DefinitionTest.php
index a363685..7510bd7 100644
--- a/tests/Type/DefinitionTest.php
+++ b/tests/Type/DefinitionTest.php
@@ -577,7 +577,7 @@ class DefinitionTest extends \PHPUnit_Framework_TestCase
         ]);
 
         $this->assertFalse($called);
-        $schema->getType('Query');
+        $schema->getType('Blog');
         $this->assertTrue($called);
 
         $this->assertEquals([$node], $blog->getInterfaces());