This book has been produced in response to an insistent demand from color workers for exhaustive information on the many forms of research that have developed the various color processes of photography into the usable condition in which they are found today. This subject was covered very completely by Professor Wall up to the time of the publication of his famous book, ""The History of Three-Color Photography,"" in 1925. But the demand for that work was so great that it has long been out of print and its information is no longer generally available. Even if it were, color photography has progressed so rapidly in the past twenty years that information as of that date could tell no more than half the story of today. To the stupendous task of ferreting out and compiling into coherent and usable form all this accumulated data, Dr. Friedman brings a splendid preparation. After graduating from Harvard and taking his doctorate at the University of Chicago, he plunged directly into color work on the staff of Technicolor which was then evolving its famous process in Boston. Through the years he has been actively identified with the development of many forms of color photography and is at present on the research staff of Ansco. He has long been known as a prolific and authoritative writer on this subject, and of late years his department in American Photography has been a general clearinghouse of information about its latest aspects. This book will be found invaluable to anyone who needs the complete record of what has gone before in any existing department of color photography. Starting with the earliest ideas of colorimetry, it traces the development of all the laboratory and commercial processes by which color has been evolved to its present-day applications, enumerating the underlying principles, describing the technique, and giving the history of the patents that have been issued concerning them. The record is as complete as it is humanly possible to achieve and contains compactly compiled and correlated information that is nowhere else available without very extensive research. For anyone who wants to get a detailed and comprehensive picture of color photography as a whole, or who needs specific information about any of its special developments, no effort has been spared to make this book as complete and valuable as possible.