A few years ago a learned bibliophile, stumbled on a 500 years old manuscript hidden among the funds of an Italian library and recognized it as the handwritten draft of a mythical book, thought lost and for centuries, actively but vainly sought after. "DE LUDO SCACHORUM" lost opus of Luca Pacioli, Franciscan friar, father of modern accounting, friend, counsellor, teacher & contributor to the century's incomparable genius, Leonardo da Vinci. The booklet is mesmerizing. It is a hand sketched draft of hundreds of complicated chess studies that Luca Pacioli must have been collecting over a long span of time. Now, perusing the booklet something catches your attention and the more you look at it the more it becomes evident. While the writing is Pacioli's, two hands instead had been there penning in the chess pieces, the first with scholarly diligence the second with artistic swiftness. Whose? Luca's and Leonardo's. They were friends, congregating and travelling together, they had a history of partnership Leonardo having illustrated Luca's DE DIVINA PROPORTIONE. It is clear: Luca was set to prepare another yet of his popularising textbooks and Leonardo had lent to his friend his "incomparable left hand" once again. Obviously the possible implication of Leonardo da Vinci in the drafting of the manuscript could not, not to be taken into consideration. And it was rejected. Rightly, at times like ours, adept to Dan Brown's like flights of fancy, doubt is a virtue and suspicion should be "de rigueur" which means that a lasting grudge must not be held to the "expert" who, possibly startled by the news, not having been warned or seen the manuscript, quipped, "the silly season on Leo never closes". In reality the discovery of Luca Pacioli's lost manuscript heralds, without doubt, that the "a la rabiosa" problems therein reported are of Leonardo's hand and we well know that Leonardo penned between 1487 and 1490 a rebus "I a roccha ro'" (I shall castle) confirming his perfect knowledge of the games new rules. These can be traced back to the coronation of queen Isabella of Spain in the year 1474 and to her crowning are dated the new powers attributed to the Bishop and the Queen whose status of most powerful piece on the chessboard justified the new rules nickname of "mad queen" or "a la rabiosa". Yet nothing is said at that time about castling, that important move absolutely necessary in modern chess to counterbalance the overpowering new status of the Queen. Nothing, from 1474 until Leonardo's rebus of 1487. Would it be its inventor Leonardo should then be considered, if such hypothetical case were true, not only the co-author as he is, of "DE LUDO SCACHORUM" and designer of the chess pieces therein drafted but, as well and rightfully, one among the major: FATHER OF MODERN CHESS. Time flies; while the excitement due to the discovery of Luca Pacioli's lost work is ineluctably subsiding, so the focus on this other of Leonardo's prodigious accomplishment is quietly worming its way into the cosy corners of expert knowledge and world oblivion. To avoid this fate this book, LEONARDO & LUCA PACIOLI - THE EVIDENCE, is set to confirm that the chess design is indeed the work of Leonardo. That two hands have been drawing the booklet's chess pieces and that, so great was his genius and so swift his incomparable left hand, that "the season on Leo still brings beautiful fruits". Supporting the evidence, you'll find, in appendix, a study of the Vitruvius Man showing its exacting geometrical structure, further to a deep reflection and elaboration of the principles Leonardo and Luca Pacioli outlined in DE DIVINA PROPORTIONE. In truth, the design of the Vitruvian Man, based on an extraordinary conception of the Golden Section, stands as a paradigm for the geometric structure and proportions of the DE LUDO SCHACORUM chessmen set. Wonder and enjoy!