This book is dedicated to the late Kenneth D. and Mary Keele.
In 1973-1974, Dr. Kenneth D. Keele, M.D., F.R.C.P. and the author reconstructed some of Leonardo's descriptions of perspective in order to determine whether these had an experimental basis. It was found that they did. The possibility that they had simply been thought experiments was excluded because some of his claims were so unlikely that they had to be tested in order to make sense. The experiments led to a long-term cooperation: first two years together as Senior Research Fellows at the Wellcome Institute for the History of Medicine (London); then with intermittent visits during the seven years while the author was at the Herzog August Bibliothek (Wolfenbüttel). As work progressed Leonardo's method became increasingly evident. The challenge of communicating this method inspired Dr. Keele to write Leonardo da Vinci's Elements of a Science of Man and led the author to write his Leonardo Studies I-II.
There have also been several attempts to make the results of these studies more accessible. In 1981 there was a published lecture on Visualisation and Perspective at the world conference on Leonardo e l'età della ragione (Milan). Here there was great enthusiasm for the sequences of diagrams, which showed a methodical approach, but the criticism was made that the order had been imposed after the fact. Rearranging Leonardo's notes did not prove that he was not chaotic: it heightened the suspicion that he was. Further study led to new evidence that this method was not merely wishful thinking, but very much a part of Leonardo's approach. This led, in February, 1984, to three lectures on Leonardo's method at Brigham Young University, organized by the kind efforts of Professor Dan Blickman. The next impulse came unexpectedly in December 1989 through an invitation to organize, with Dr. Michael Sukale, a section at the European Forum (Alpbach) on Leonardo's Laws of Vision and of Nature. By way of preparation the notebooks were reread and this brought to light Leonardo's lists with their systematic play of variables. An essay was written in haste, which was not suited to the format of the proceedings in Alpbach. So it was distributed to a few friends for criticism and allowed to mature. What follows is the result.