1589. BOOK: (POLIORECTIC). THETI, CARLO: DISCORSI DELLE FORTIFICATIONI, Espugnationi, & Difese delle Città, & d'altri Luoghi. Division in libri otto... Venetia: Appresso Francesco de Franceschi Senese, 1589. Folio mayor. Book I and II: 2 h. + 2 h. + 47 p. + 3 sheets (2 doubles). Book III, IV, V and VI: 2 h. + 86 p. + 15 plates (10 of which are doubles). Book VII and VIII: 68 p. + 2 plates (one double); missing from the last booklet (pp. 69-72). Some errors of pagination (in Book I: jump p. 20 to 25 and repetition of pp. 25-28). Cover with beautiful typographical markings, with some minor errors on the outer margin and some small stains. Fourth book with its own cover. Illustrated with headers, capitals and culs-de-lampe; a multitude of woodcut figures in the text and planimetries, sections and other vignettes, some of them double, inside and outside the text, illustrate the topographic technique up to different defensive and offensive elements of the fortifications. Small lack due to ink corrosion between pages 19 to 24. Very fine and intermittent gallery, does not affect text. Some old handwritten annotation. Enc. in the middle of modern parchment, labeled hillock. We present the reference work of the engineering of fortresses that gave rise to the conception of modern polyurethane. C. Theti was one of the pioneers of modern military engineering, advisor to the Medici or tutor to Prince Maximilian II. The piece that we present corresponds to the best edition of the famous book by Theti, after the short edition of 1569 and the edition of 1575, which only contains two books. CCPB 26058-4.