This is a rare and valuable collectible for aviation enthusiasts. The Civil Pilot Training Manual, with Civil Aeronautics Admin. No.23, is a must-have for anyone interested in the history of aviation. This manual is a comprehensive guide for civil pilots and covers all aspects of their training and development. It was published in September 1941 in the United States and is an excellent example of the quality of aviation education at that time. The manual is designed for those interested in pursuing a career in aviation and provides detailed information on the training and certification process. It is a valuable addition to any collection of aviation memorabilia and is a true testament to the rich history of aviation in the United States.