In World War II the international YMCA gave prisoners of war hardcover books with blank pages. POW's filled these with writing and drawings, often from fellow POW's. I will be selling one that belong to a POW who was a fighter pilot and a senior POW at Stalag Luft III. His book included a note apparently smuggled to his camp from four airmen held elsewhere after beind tried as spies. The note was originally folded to about one by two inches in size.
