Cephalopods are diverse, highly developed molluscs capable of swimming and jet propulsion. These animals are an important component of present-day marine ecosystems throughout the world and comprise approximately 900 species. They also have an extraordinary fossil record, extending back to the Cambrian Period, with as many as 10,000 extinct species. Throughout their long history, they have experienced sp- tacular radiations and near-total extinctions. Because of their superb fossil record, they also serve as ideal index fossils to subdivide geologic time. This book touches on many of these themes, and it treats both fossil and present-day cephalopods. The chapters are outgrowths of presentations at the Sixth International Symposium “Cephalopods – Present and Past,” at the University of Arkansas in Fayetteville, September 16–19, 2004. The Symposium was organized principally by Walter L. Manger of the Department of Geology, University of Arkansas. The editors gratefully acknowledge Walter for his terrific job in putting together this symposium and for making it such an intellectual, and social, success. Other publications related to this Symposium include the abstract volume, assembled by W. L. Manger, and two fie- trip guidebooks, one written by W. L. Manger, and the other by R. H. Mapes. Because this symposium was held in North America, it honored four cephalopod workers from this continent: William A. Cobban (US Geological Survey, Denver, Colorado), Brian F. Glenister (University of Iowa, Iowa City, Iowa), William M. Furnish (University of Iowa, Iowa City, Iowa), and Gerd E. G.