diff --git a/Facepunch.Steamworks.Test/Client/Workshop.cs b/Facepunch.Steamworks.Test/Client/Workshop.cs
index 0b45c10..b1b6eb4 100644
--- a/Facepunch.Steamworks.Test/Client/Workshop.cs
+++ b/Facepunch.Steamworks.Test/Client/Workshop.cs
@@ -129,5 +129,63 @@ namespace Facepunch.Steamworks.Test
             }
         }
 
+        [TestMethod]
+        public void QueryFile()
+        {
+            using ( var client = new Facepunch.Steamworks.Client( 252490 ) )
+            {
+                Assert.IsTrue( client.IsValid );
+
+                using ( var Query = client.Workshop.CreateQuery() )
+                {
+                    Query.FileId.Add( 751993251 );
+                    Query.Run();
+
+                    Assert.IsTrue( Query.IsRunning );
+
+                    Query.Block();
+
+                    Assert.IsFalse( Query.IsRunning );
+                    Assert.AreEqual( Query.TotalResults, 1 );
+                    Assert.AreEqual( Query.Items.Length, 1 );
+
+                    Console.WriteLine( "Query.TotalResults: {0}", Query.TotalResults );
+                    Console.WriteLine( "Query.Items.Length: {0}", Query.Items.Length );
+
+                    Assert.AreEqual<ulong>( Query.Items[0].Id, 751993251 );
+                }
+            }
+        }
+
+        [TestMethod]
+        public void QueryFiles()
+        {
+            using ( var client = new Facepunch.Steamworks.Client( 252490 ) )
+            {
+                Assert.IsTrue( client.IsValid );
+
+                using ( var Query = client.Workshop.CreateQuery() )
+                {
+                    Query.FileId.Add( 751993251 );
+                    Query.FileId.Add( 747266909 );
+                    Query.Run();
+
+                    Assert.IsTrue( Query.IsRunning );
+
+                    Query.Block();
+
+                    Assert.IsFalse( Query.IsRunning );
+                    Assert.AreEqual( Query.TotalResults, 2 );
+                    Assert.AreEqual( Query.Items.Length, 2 );
+
+                    Console.WriteLine( "Query.TotalResults: {0}", Query.TotalResults );
+                    Console.WriteLine( "Query.Items.Length: {0}", Query.Items.Length );
+
+                    Assert.IsTrue( Query.Items.Any( x => x.Id == 751993251 ) );
+                    Assert.IsTrue( Query.Items.Any( x => x.Id == 747266909 ) );
+                }
+            }
+        }
+
     }
 }
diff --git a/Facepunch.Steamworks/Interfaces/Workshop.cs b/Facepunch.Steamworks/Interfaces/Workshop.cs
index d90b4e7..753ddbd 100644
--- a/Facepunch.Steamworks/Interfaces/Workshop.cs
+++ b/Facepunch.Steamworks/Interfaces/Workshop.cs
@@ -128,7 +128,7 @@ namespace Facepunch.Steamworks
             public int Page { get; set; } = 1;
             internal Workshop workshop;
 
-            public void Run()
+            public unsafe void Run()
             {
                 if ( Callback != null )
                     return;
@@ -136,7 +136,21 @@ namespace Facepunch.Steamworks
                 if ( Page <= 0 )
                     throw new System.Exception( "Page should be 1 or above" );
 
-                Handle = workshop.ugc.CreateQueryAllUGCRequest( (uint)Order, (uint)QueryType, UploaderAppId, AppId,( uint)Page );
+                if ( FileId.Count != 0 )
+                {
+                    var fileArray = FileId.ToArray();
+
+                    fixed ( ulong* array = fileArray )
+                    {
+                        Handle = workshop.ugc.CreateQueryUGCDetailsRequest( (IntPtr) array, (uint)fileArray.Length );
+                    }
+                }
+                else
+                {
+                    Handle = workshop.ugc.CreateQueryAllUGCRequest( (uint)Order, (uint)QueryType, UploaderAppId, AppId, (uint)Page );
+                }
+
+                
 
                 if ( !string.IsNullOrEmpty( SearchText ) )
                     workshop.ugc.SetSearchText( Handle, SearchText );
@@ -195,6 +209,11 @@ namespace Facepunch.Steamworks
             /// </summary>
             public List<string> ExcludeTags { get; set; } = new List<string>();
 
+            /// <summary>
+            /// If you're querying for a particular file or files, add them to this.
+            /// </summary>
+            public List<ulong> FileId { get; set; } = new List<ulong>();
+
             /// <summary>
             /// Don't call this in production!
             /// </summary>
diff --git a/Facepunch.Steamworks/Interop/steam_api_interop.cs b/Facepunch.Steamworks/Interop/steam_api_interop.cs
index c8e6f9b..a0022f8 100644
--- a/Facepunch.Steamworks/Interop/steam_api_interop.cs
+++ b/Facepunch.Steamworks/Interop/steam_api_interop.cs
@@ -976,7 +976,7 @@ namespace Valve.Interop
         [DllImportAttribute( Config.LibraryName, CallingConvention = CallingConvention.Cdecl, EntryPoint = "SteamAPI_ISteamUGC_CreateQueryAllUGCRequest" )]
         internal static extern ulong SteamAPI_ISteamUGC_CreateQueryAllUGCRequest( IntPtr instancePtr, uint eQueryType, uint eMatchingeMatchingUGCTypeFileType, uint nCreatorAppID, uint nConsumerAppID, uint unPage );
         [DllImportAttribute( Config.LibraryName, CallingConvention = CallingConvention.Cdecl, EntryPoint = "SteamAPI_ISteamUGC_CreateQueryUGCDetailsRequest" )]
-        internal static extern ulong SteamAPI_ISteamUGC_CreateQueryUGCDetailsRequest( IntPtr instancePtr, ref ulong pvecPublishedFileID, uint unNumPublishedFileIDs );
+        internal static unsafe extern ulong SteamAPI_ISteamUGC_CreateQueryUGCDetailsRequest( IntPtr instancePtr, IntPtr pvecPublishedFileID, uint unNumPublishedFileIDs );
         [DllImportAttribute( Config.LibraryName, CallingConvention = CallingConvention.Cdecl, EntryPoint = "SteamAPI_ISteamUGC_SendQueryUGCRequest" )]
         internal static extern ulong SteamAPI_ISteamUGC_SendQueryUGCRequest( IntPtr instancePtr, ulong handle );
         [DllImportAttribute( Config.LibraryName, CallingConvention = CallingConvention.Cdecl, EntryPoint = "SteamAPI_ISteamUGC_GetQueryUGCResult" )]
@@ -2173,7 +2173,7 @@ namespace Valve.Steamworks
         internal abstract IntPtr GetIntPtr();
         internal abstract ulong CreateQueryUserUGCRequest( uint unAccountID, uint eListType, uint eMatchingUGCType, uint eSortOrder, uint nCreatorAppID, uint nConsumerAppID, uint unPage );
         internal abstract ulong CreateQueryAllUGCRequest( uint eQueryType, uint eMatchingeMatchingUGCTypeFileType, uint nCreatorAppID, uint nConsumerAppID, uint unPage );
-        internal abstract ulong CreateQueryUGCDetailsRequest( ref ulong pvecPublishedFileID, uint unNumPublishedFileIDs );
+        internal abstract ulong CreateQueryUGCDetailsRequest( IntPtr pvecPublishedFileID, uint unNumPublishedFileIDs );
         internal abstract ulong SendQueryUGCRequest( ulong handle );
         internal abstract bool GetQueryUGCResult( ulong handle, uint index, ref SteamUGCDetails_t pDetails );
         internal abstract bool GetQueryUGCPreviewURL( ulong handle, uint index, out string pchURL );
@@ -5631,11 +5631,10 @@ namespace Valve.Steamworks
             ulong result = NativeEntrypoints.SteamAPI_ISteamUGC_CreateQueryAllUGCRequest(m_pSteamUGC,eQueryType,eMatchingeMatchingUGCTypeFileType,nCreatorAppID,nConsumerAppID,unPage);
             return result;
         }
-        internal override ulong CreateQueryUGCDetailsRequest( ref ulong pvecPublishedFileID, uint unNumPublishedFileIDs )
+        internal override ulong CreateQueryUGCDetailsRequest( IntPtr pvecPublishedFileID, uint unNumPublishedFileIDs )
         {
             CheckIfUsable();
-            pvecPublishedFileID = 0;
-            ulong result = NativeEntrypoints.SteamAPI_ISteamUGC_CreateQueryUGCDetailsRequest(m_pSteamUGC,ref pvecPublishedFileID,unNumPublishedFileIDs);
+            ulong result = NativeEntrypoints.SteamAPI_ISteamUGC_CreateQueryUGCDetailsRequest(m_pSteamUGC, pvecPublishedFileID,unNumPublishedFileIDs);
             return result;
         }
         internal override ulong SendQueryUGCRequest( ulong handle )