The Jemez Mountains are one of the most intensively studied mountain ranges in North America, and probably in the world. Best known for the early Pleistocene Valles caldera, the world's type example of a resurgent caldera, the Jemez Mountains also includes a wide variety of other volcanic features, both older and younger than the caldera. Field and laboratory studies of the Jemez region, by scores of geoscientists at numerous institutions, have produced a remarkable amount of new information over the past decade. In addition, much new research on individual volcanic units, Cenozoic stratigraphy and structure of the Espan?ola Basin, hydrology and environmental geology, and Pleistocene-Holocene stratigraphy, geomorphology, and archeology is presented in this guidebook. There are two versions of this guidebook available--the complete guidebook (499 pages), and a version with just the road logs that is spiral bound (146 pages). --New Mexico Geological Society website.