Most class books in the collection are from different air fields and training centers. Pilot training involved pre-flight, primary, basic, advanced, transition and unit training. After graduating one course, cadets were generally re-assigned to another air field for the next phase of their training. Interestingly, there seem to be no class books published for transition and unit training programs.
Here are the phases of pilot training as they were in 1944, adapted from The Official Guide to the Army Air Forces (New York: Pocket Books, Inc., May 1944).