Today's book is Pistols of World War I, by Robert J. Adamek. It's a good overview of all the significant handguns used by combatants on both sides of the war (90 pistols among 16 countries). There isn't a whole lot of description and history for each individual gun, but they do each have statistics on production and adoption quantities, dimensioned sketches of cartridges and magazines, and basic disassembly instructions.