This is a simple Prolog interpreter that is compatible with Unity3D, allowing Prolog code to be mixed with the standard Unity-supported languages. It is open source (MIT License), but is easiest to use by grabbing the DLL and placing it in the Assets folder of your Unity project. You also need to copy the files in the Editor subdirectory to the Editor directory of your Unity project; these will ensure that your .prolog files get copied over to your standalone builds so that they can be loaded. See the Documentation folder for more information. To compile the code on your own, you either need to copy the Prolog directory into your Unity project, or build the DLL on your own using Visual Studio. The latter will require that you put a copy of the UnityEngine.dll file from the Unity3D distribution in the top-level directory of the Visual Studio project. The Unity DLL is not distributed with the source for copyright reasons. Please direct any questions to Ian Horswill .