When published in 1971, Principles of Paleontology (POP) by David Raup and Steven Stanley revolutionized both textbooks and teaching in paleontology by adopting an approach that focused on the process of studying biologic groups, rather than a systematic approach (the study of individual groups of organisms), or an historical approach (narrating events to date).  For this highly anticipated revision of Raup and Stanley's one-term undergraduate text, two of Raup's former students--Michael Foote and Arnold Miller--use that defining core approach to present a thoroughly up-to-date portrait of a field that has undergone major transformations in the last two decades.