This monograph is the most comprehensive treatment available of the geology of the Santa Catalina Mountains north of Tucson, expanding greatly on classic older descriptions of the southern Catalinas. The study treats the entire range with a cross-sectional emphasis to clarify relations among the mylonitic core-complex aspects to the south, passing northward through voluminous Tertiary granitic rocks and an older deformed and metamorphosed zone into a tilted relic of the Plateau. New rock units such as Precambrian glaciomarine deposits are introduced, and the mineral-resource character and potential of each segment of the range is described. The book includes a full-color 1:48,000 geologic map of an 11 x 48 km transect through the range, oriented to permit reconstruction of the jigsaw puzzle produced by Tertiary crustal stretching. Three other detailed maps and descriptions of key localities make the monograph a self-guided tour through the geologic history of the range.