The Treatise on Paint by Gianni Maimeri (1884-1951) is an unpublished manuscript in the author's own hand by one of the most unusual Italian artists of the early twentieth century. Founder of one of the country's most successful manufacturers of paints for the fine arts, still in operation and well-known the world over, the author managed to continue a very active career as a painter without interruption while running a business and accumulating a degree of technical know-how that was uncommon in his day. The Treatise on Paint, which Gianni Maimeri wrote as a mature man, occupies a unique position in the context of early twentieth century trends in technical and artistic publications in Italy and Europe. Difficulties linked with World War II and problems in the business, followed by the author's death, made it impossible to publish the manuscript until its recent rediscovery. This edition of the text, edited by Sandro Baroni, preserves the author's changes to illustrate his thought processes as he wrote the text, and is accompanied by a number of useful tools: a technical glossary by Luigi Brusati and a bibliography by Paola Travaglio on the orientation of Italian publications in the sector. The appendix includes biographical notes on the author by Carlo Migliavacca and notes on his artistic career and exhibitions of his works by Paola Travaglio and Maite Rossi.