Since colonial times Americans have used the militia to maintain local order during both war and peacetime. States have intermittently created, maintained, deployed, and disbanded countless militia organizations outside the scope of the better-known National Guard. Barry M. Stentiford tells the story of these militia units—variously called home guards, State Guard, National Guard Reserve, and State Defense Forces. Stentiford traces the evolution of the militia over the past century, demonstrating its transformation from an amalgamation of state militia units into the National Guard, a reserve of the army. Ironically, the very existence of the National Guard made the creation of other militia forces necessary during periods of war. The home guards or State Guard were organized to fill the vacuum left when the National Guard was called up, depriving states of an organized militia that could be mobilized for repelling invasions, suppressing riots, controlling strikes, or guarding the waterfront. Stentiford carefully analyzes the challenges that faced the State Guards as states sought to build their new militia with leftover men and material. He also examines the role of the State Guard: providing relief during and after natural disasters, providing military training for future draftees, and broadening participation in military units during wartime by giving a role to men who, because of their age or occupation, could not join the federal forces. The State Guard gained a new significance in the Cold War, especially as the political unpalatability of a draft and reductions in the size of the full-time military expanded the functions of the National Guard in military policy. Today modern state militias, born to an ancient tradition, must define a role for themselves in a society that increasingly views them as anachronistic. They mut also compete ideologically with so-called unorganized militias for the title of true heir to the American militia tradition.