La fortification perpendiculaire, ou essai sur plusieurs manieres de fortifier la ligne droite, le triangle, le quarré, & tous les polygônes, ...Paris, Philippe-Denys Pierres, 1776-1778. 4 (of 5) volumes. Large 4to. With an engraved portrait of the author as frontispiece in volume 1 and with a total of 87 folding engraved plates. Contemporary calf, richly gold-tooled spine.

[8], XL, 225, [7]; [6], XVI, 322, [4]; [12], XL, 248, [2]; [4], 397, [3] pp.First edition of a very extensive work on fortification, by the French military engineer Marc-René, marquis de Montalembert (1714-1800). "Viewing fortresses as nothing more than immense permanent batteries designed to pour overwhelming fire on attacking armies, Montalembert simplified the intricate geometric designs of Vauban and relied on simple polygonal structures, often with detached peripheral forts instead of projecting bastions. The fortifications at Anklam, Stralsund, Aix-en-Provence, and Île d'Oléron were among his most prominent creations." (Encyclopaedia Brittanica). The first volume is devoted to the origins and progress of fortification, the others to the usefulness, construction, attack, defence and other aspects of fortresses. A fifth volume with 17 folding plates, added in 1784, is not included in the present set, which was probably issued before it appeared.With several library- and deaccession stamps. Occasionally some minor foxing and some marginal (water) stains. Some plates slightly browned and a few with frayed edges. Overall in very good condition and with wide margins. Bindings somewhat rubbed, some tiny wormholes, but still firm and good.l Encyclopaedia Brittanica, Marc-René, marquis de Montalembert (online); Jähns, p. 1863; Jordan 2561; Sloos, Warfare 08168.