Abstract Here is a new, state-of-the-art guide for assessing earthquake sources throughout the contiguous United States. Because the relevant literature on the geological aspects of earthquake assessment has become so extensive in recent years, scientists should welcome this timely and compact group of new, useful syntheses of current knowledge addressing recent developments in the principal seismically active regions of the United States: the Pacific Coast; the western mountain area; the New Madrid area; New England; and the southeastern United States, including Charleston, South Carolina. Among the contributors are researchers who have made notable contributions to the art in their own right, making this an especially valuable new tool.