This volume was prepared primarily for aid in the training and supervision of roentgenographic technicians and secondarily for the use of the general medical profession. It is written in simple language and published by the lithographic printing method to provide flexibility in making additions to and eliminations from the text. After a brief historical introduction the book develops the subject from a physical and mechanical point of view of x-ray technic and then discusses essential factors in roentgenologic procedure and dark room technic. The remaining portions of the book are concerned with standard precautions for protection from excessive x-ray exposure and instructions to the technician. The book is plentifully supplied with excellent illustrations, with pages for inserted notes and with a comprehensive and excellent index. Its wide use in schools for x-ray technicians has established its practical character.