This is a very old (from 1930s-1940s) and RARE instruction manual by International Business Machines (IBM) for customer engineering and servicing of their equipment, such as early typewriters and card punch machines. There are multi-sectioned documents filled with instructions, diagrams, and procedures to help technicians service and repair IBM products. Includes customer service instructions and schematics. It’s in solid preowned condition with some typical wear and tear for its age. RARE BOOK.