The Book of GENESIS" is in two parts. Firstly, a collection of contributed articles describes projects created using the GENESIS system, and then a step-by-step tutorial explains how the software works and how best to manipulate it so as to achieve maximum use. As a result, this publication may be seen as a reference guide, a textbook for course use, and as a resource to which readers can turn for ideas on how to devise their own models and applications. The accompanying cross-platform CD-ROM contains the full source code for GENESIS and its graphical interface, XODUS, the GENESIS Reference Manual in hypertext, plain text and Postscript formats, numerous tutorial simulations and example simulation scripts, including all of those used in the book. As a bonus, also included on the CD are a number of items which are not part of the standard distribution of GENESIS. The GENESIS system will continue to be made available through the Cal Tech World Wide Web site, as well, at: www.bbb.caltech.edu/GENESIS.