Reviews the history of the development of photocopying processes. A brief description is given of the work of Chester F. Carlson who invented the technology of electrophotography -- later called xerography -- in 1938. A quote from Dr. John H. Dessauer who headed the research team that developed the process explains the basic principles of the technique, and the developments in the variety of photoconductors and other materials and equipment used. The impact of the photocopier on paper proliferation is mentioned, as is the unavoidable overload due to the differences in copy quality and long-term durability. The criteria for archival quality copies are discussed. They apply to paper, pigments, toners, and methods.