Though the epicenter of this marvelously constructed book is San Francisco, Winchester covers much more than just the disaster. He discusses how this particular quake led to greater scientific study of quakes in an attempt to understand the movements of the earth. Trained at Oxford University as a geologist, Winchester is well qualified to discuss the subject, and he clearly explains plate tectonics theory (first introduced in 1968) and the creation of the San Andreas Fault, along with the geologic exploration of the American West in the late 19th century and the evolution of technology used to measure and predict earthquakes. He also covers the social and political shifts caused by the disaster, such as the way that Pentecostalists viewed the quake as "a message of divine approval" and used it to recruit new members into the church, and the rise in the local Chinese population. With many records destroyed in the fire, there was no way to distinguish between legal and illegal immigrants, and thus many more Chinese were granted citizenship than would have otherwise been. Filled with eyewitness accounts, vivid descriptions, crisp prose, and many delightful meanderings, A Crack in the Edge of the World is a thoroughly absorbing tale. --Shawn Carkonen