We have reported on two books for adult ""rockhounds"" prior to this:- Fritzen's The Rock-Hunter's Field Manual (Harper- 1959), which was a good basic field guide; and Pearl's How To Know the Minerals and Rock (McGraw-Hill- 1954) which is an identification book. The current book includes both topics, and should- for some time to come-prove to be definitive for informed and enthusiastic amateur collectors. Though subtitled How and Where To Find Minerals and Gem Stones in the United States, this is much more than a guide. The author provides considerable information of a technical and scientific nature on classification under the specific chemical families as the simplest approach; on field identification, based on the geologic timetables and the three basic types of rocks (igneous, including pegmatite, on sedimentaries, on metamorphic rocks). He discusses the geologic maps as indispensable field aids, and how to use them to best advantage. He provides data on preparation for field trips, on tools and equipment, on clothing, camping provisions, wrappings for protecting finds; on beginning a collection; on what sorts of notes and records to keep -- an important initial piece of advice often ignored; what to do with surplus, how to prepare, store and display specimens, how to get the most out of what is a steadily growing hobby -- this rounds out a very practical and complete hobby book. The final section proceeds state by state to indicate areas, and what is found there, while the appendix lists museums and provides an extensive bibliography. This book should be in both public and school libraries.