This is the definitive reference for version 3.4 of the mental ray(R) image rendering software. Beginning with a brief overview of mental ray features, it includes specifications of the mental ray scene description language, the mental ray shader interface, and the integration interface for third-party applications. The material is organized by grammar elements and C function call, for quick reference. The new third edition is expanded to encompass mental ray 3.4, and includes the mental ray integration manual. The enclosed CD contains a demo version of the mental ray stand alone and the mental ray library, plus sample shaders with source code and demo scenes, for a variety of computer platforms.