This Book provides a How-To Guide for the novice gun builder as-well-as the experienced gunsmith in the construction of six of the more prominent types of Underhammer Muzzleloader Locks; Carleton, Chase, Cook, Cooper, Hilliard, and Wood. Both general and specific lock construction techniques designed primarily to use common workshop tools are given. Full sized illustrations and a blown up drawing of each the selected Underhammer Locks are provided.