This book summarizes recent advances in information on the porphyry copper deposits of southwestern North America. It is a sequel to a n earlier summary volume published by the same group in 1966. The new volume is indispensable for anyone interested in copper deposits and a valuable reference for those working in fields ranging from the petrology of silicic igneous rocks to the tectonic evolution of western North America. The volume is particularly significant because porphyry coppers are by far the most important class of deposits in terms of global copper reserves and, most importantly, because southwestern North America contains an unusually large number and variety of these deposits.