Book excerpt: This book evolved from a course on the natural history of the Anza-Borrego region that was developed by the authors over a 16-year period and taught at the University of San Diego. It tells a coherent story of how the landscape and features of a desert region evolved over time and how organisms that inhabit the desert have adapted to the conditions found there by taking many different evolutionary paths to deal with aridity, heat, and saline soils. The result is an amazing biological diversity that has evolved in response to these conditions. This book is encyclopedic in detail and is yet very readable. Each illustration was handcrafted to tell a story and to help the reader better understand the fascinating story of this unique desert place and its first human inhabitants. This is the "go-to" book for anyone wanting to understand the natural environment of the Anza-Borrego region