A Hidden IT “Best Seller”: IBM Customer Engineering Maintenance Manuals, 1930s–1980s

IBM published a large body of technical manuals that described how to install, repair, and maintain its products during the 20th century. These were only available to the many thousands of IBM customer engineers. They remain a source of IT literature that historians have yet to study. This article describes these collections and recommends what historians and archivists should do about them.