A close look at the conception, construction, function, and operation of the famous ""impregnable"" Maginot Line--chiefly, at this date, for fortifications-buffs. Kemp is hardly the first, that is, to explode the ""myth"" that the enormously costly fortification zone was designed to withstand a German assault; it was intended, rather, to force the Germans to attack through Belgium in any future conflict, thereby assuring a British response--and in that aim, it was successful. (The fact that the French were then undone is another story--of their failure to keep up with developments in mechanized warfare and their general moral collapse.) After minutely examining the construction of the forts (down to the air-conditioning system, devised to deal with gas attacks), Kemp scrutinizes the internal operations of a typical fort: its habitability, fire control, drainage, ammunition supply, etc. Pondering how the Maginot Line might have been used, he notes that it could have served as a base for a French invasion of Germany while the Nazis were occupied with Poland in 1939 and, less plausibly, served the same purpose for a thrust across the German line of communications during the Battle for France. But though he carries the story to the present, with directions on tours of the line, he fails to mention that NATO seriously considered reactivating the line in the event of a Soviet attack in the early 1950s. While much of the material is familiar from Vivian Rowe's 1961 The Great Wall of France, Kemp--also author of the recent The Unknown Battle: Metz, 1944--fills in considerable technical and operational detail.