"The Book of GENESIS" thoroughly and accurately describes this UNIX -based neuroscience modeling and simulation software developed over a number of years through NSF funding at Cal Tech. It consists of two parts. First, a collection of eight interactive computer tutorials describing simulation projects created using the GENESIS system, and second, a step-by-step practical guide which explains how the GENESIS software works and how to best manipulate it to achieve maximum results in creating one's own simulations. This publication has application as a reference guide, a textbook for course use, and as a resource to which readers can turn for ideas on how to devise one's own models and applications using the GENESIS software system. The 1st Edition of the "Book of GENESIS" was based on GENESIS version 2.0. Since its publication in 1994, there have been two further versions of GENESIS, 2.0.1 and 2.0.2 Also, two new auxillary libraries, i.e., Kinetics and pGENESIS, which extend the functionality of GENESIS. In 1997, GENESIS 2.1 will appear at approximately the same time as the revision of this book. In thje new edition, there have been several changes made to the text of the book, itself, including the incorporation of two new chapters. In Part One, a new chapter on "Biochemical Kinetic Models" by U.S. Bhalla, and in Part Two, a new chapter on "Parallel Simulation of GENESIS Models" contributed by N.Goddard and G.Hood. In addition, most chapters have been improved slightly and updated, while Chapters 14, 18 and 19 have been even more significantly reworked for this new edition. The inclusion of a cross-platform CD-ROM to accompany the printed text greatly expands the utility of the GENESIS system. The cross-platform CD-ROM now accompanying the book "The Book of GENESIS" contains the full source code for GENESIS and its graphical