"In the Darkroom" is a compilation of essential information about the predominant negative, positive and photomechanical processes in use since 1839. Entries include concise technical descriptions of the processes and their common uses, museum-quality illustrations (some at high magnification to show print characteristics), and diagrams indicating the basic structure of the print or negative. Processes are arranged alphabetically for easy reference. The guide also includes a time line with the major dates of use for each process, an extensive glossary, and an index of variant names.