Today we laugh at "Dad's Army", but in 1940 the threat of a German invasion of Britain was a very real one. S. P. MacKenzie's detailed history of the Home Guard offers a new perspective on the men who took up the challenge. Despite its popular image of old men and teenagers playing soldiers, the Home Guard, often as large as the wartime army, became an astonishingly strong political force in its own right. Quite literally the people in arms, it proved able to exert a good deal of influence on policy. The threat of invasion receded and the Home Guard was never called upon to fulfil its military role, though there was a brief attempt to resurrect it in the 1950s. Since then it has been largely neglected by military historians and there have been few serious examinations of the part it played in the Home Front.