Pacioli (Luca) Divina proporzione opera a tutti glingegni perspicaci e curiosi necessaria, 23ff., comprising the "Golden Alphabet" only, printed on recto only (the alphabet contains two letters 'O' but omits letter 'Z'), letter 'A' supplied in facsimile on antique paper, marginal stain to first leaf, traces of fingerprints and some spots throughout, but all in all a very well preserved copy with wide margins, last leaf recto paper strip with the note "Cat. 40 Estanislao Rodriguez 1931" pasted on, modern reddish-brown morocco tooled in blind in antique style, by Bernard Middleton, preserved in modern brown cloth slip-case, folio, Venice, Paganino Paganini, 1509.

⁂ A proof copy of the celebrated alphabet from Pacioli's masterpiece, the Divina Proporzione, a treatise on the "divine proportion" or, as it is also called, the "golden section" or "golden ratio". The Divina Proporzione is the first printed book to deal with the construction of the alphabet and to examine the shapes and proportions of classical Roman letters. Pacioli's alphabet was designed after the work of his mentor Leonardo da Vinci as a model of perfection for carving epitaphs and inscriptions.

Compared to the final version, the present copy bears for each letter a guide letter stamped by hand, using metal types, in the blank space of the woodcut, accompanied in most cases by a shadow letter guide, which is stamped in blank either beside the other one or just outside the woodcut. In letter 'K' the guide letter is wrongly an 'I' (it would appear that the printer did not have a Roman 'K' at his disposaland even in the explanatory text below the woodcut he uses a gothic 'k'). The guide letters were apparently intended to ensure that the woodcuts were printed on the correct page. From their erratic placement and orientation - inside or outside the frame of the woodcut capital letters - it is evident that they were stamped on the sheets by hand using metal types and they could not have been printed in the press at the same time as the short text below. As for the explanatory texts below the woodcuts, this does not differ from that of the final version, with the the only exception of letter 'N', where the text ends with a paragraph mark or a lowercase 'u' that does not appear in any examined copy of the book. All these elements lead to the conclusion that this is a proof state copy of Pacioli's alphabet, representing a quite exceptional discovery and an important document in the history of the printing.

The proportion, which for centuries intrigued the minds of mathematicians and artists, also preoccupied Piero della Francesca, of whom Pacioli was a pupil and a friend, and Leonardo da Vinci, to whom the plates that illustrate the Divina Proporzione are attributed. In 1508 Pacioli gave some lessons in Venice, at the Rialto School, on Euclid's Elements, and the following year he published a new edition of the work. Many eminent personalities of the time attended these lessons, including Aldus Manutius and Fra' Giocondo. It was probably on that occasion that he got the idea of publishing a practical treatise on proportion.

The encounter between Pacioli and the technical genius of Paganini gave birth to an unprecedented work, in which the lay-out of the edition admirably matches the content of the book. Even though it was never reprinted (presumably due to technical difficulties) and despite being seemingly forgotten for many years, the Divina proporzione was enormously influential, especially in the arts and in the history of printing, and also represents a milestone in the tradition of calligraphic printed books (cf. S. Morison, Pacioli's Classic Roman Alphabet, New York, 1933).