Approximately 45 books in total. Some titles to include: "Packing Iron: Gunleather of the Old West" by Richard C. Rattenbury, "Spencer Repeating Firearms" by Roy M. Marcot, "Sharps Firearms" by Frank Sellers, "Trapdoor Springfield" by M.D. "Bud" Waite & B.D. Ernst, and "The Browning High Power Automatic Pistol" by R. Blake Stevens.