This is less a history of medieval or specifically Gothic architecture (either design or construction) than a conjectural account of related circumstances--who did what and why. The focus is appropriately on France but only in the brief terminal chapter on International Gothic is there a coherent explanation of stylistic evolution (in England) helpfully illustrated; in the body of the book, the uninformed reader has to wait until page 100, in the section on Chartres as representative, for definition and depiction of the three fundamental structural features; the pointed arch, the ribbed vault and the flying buttress. Mr. Jacobs and his collaborators make much of the role of masons, even call Villard de Honnecourt a mason, an instance of carrying a fruitful approach too far. The book is a selective construct altogether rather than a study, and neither strictly chronological nor comprehensive; moreover, many of the illustrations are more attractive than germane. The student needs a more meticulous introduction and anyone will have to take some of this on faith.