This unique book takes a thematic approach to twentieth century photography, enabling the reader to distinguish among the complex processes and practitioners of the period. It focuses on the major developments of each of the 20-year periods into which the book is divided rather than on individual photographers. Information on photographers is referenced at the end of each section for further study. The book is unique in the literature of photography in that it contains an introductory overview of each chronological period that provides a context for the writings of the major critics within each period.