Here are three reference books related to boilers from the Japan Boiler Association: * Boiler Operation Skills Training Textbook * Boiler Illustrated Encyclopedia * Boiler and Pressure Vessel Safety Regulations They are in clean condition with no noticeable scratches, folds, or stains. There are some parts with markings in marker or colored pen. I will respond to requests such as showing detailed images. Illustrated encyclopedia containing detailed technical information on boilers. * Title: Boiler Illustrated Encyclopedia * Author: Japan Boiler Association * Contents: Technical information and illustrations related to boilers * Language: Japanese * Condition: Good Thank you for viewing.