Seen in perspective, this is probably the single longest chapter in this book. And still, there's no way we have covered all the material I initially intended. Many areas like BRDF real-time rendering, dynamic light mapping, BTDFs (the equivalent of a BRDF for transmitted and nonreflected light), and nonphotorealistic rendering are some of today's hottest research topics, so the amount of documentation and bibliography is overwhelming. This chapter is thus little more than an eye-opener. Check out the materials quoted in Appendix E, "Further Reading."