This appendix provides a brief introduction to the Microsoft DirectX technology for rendering 3D graphics. A full-blown tutorial of the API would require hundreds of pages and is by no means the goal of this book. However, I felt it was important to offer some preliminary information, so you can get coding soon. Thus, this appendix only attempts to cover the essentials of Direct3D: its main components, how to work with them, and so on. Other chapters in the book provide more involved examples for specific applications.