Approximately 25 books covering topics of WWII. Some examples are "Geronimo! U.S. Airborne Uniforms, Insignia & Equipment in World War II" by Rentz, "Sniper Variations of the German K98k Rifle" by Law, "World War II Collectibles" by Graf, "SS HELMETS THE HISTORY, USE AND DECORATION OF THE HELMETS OF THE BLACK CORPS" by Beaver/Hicks, "Imperial Japanese Army and Navy Uniforms & Epuipment" by Nakata/Nelson, "SOLDAT" volumes 3,5,11 and 11C.