John Dee, an English mathematician, alchemist, and all-round proto-polymath, was born July 13, 1527. Dee is better known today than many of his contemporaries, in a notorious sort of way, because of his involvement with Edward Kelley, an alchemical scoundrel who came into Dee’s life when Dee was nearly 60 and managed to thoroughly ruin Dee’s reputation and fortune. But Dee was actually a multi-talented fellow, and he should be remembered today for a remarkable preface that he wrote for the first English edition of Euclid’s Elements (1570), sometimes called the Billingsley Euclid, after the name of the translator, but just as often referred to as Dee’s Euclid, because of his remarkable preliminary essay, usually called “Dee’s Preface.” The second image shows the woodcut title-page to Dee’s Euclid, and the third a detail of the box that proclaims Dee’s contribution.

Laypeople often wonder why historians give so much attention to Renaissance alchemists and natural magicians, such as Dee and Giovanni Battista della Porta, when we all know that alchemy, magic, astrology, and numerology have nothing to do with science. You will find the answer in Dee’s Preface. Dee argues for the importance of mathematics in all the sciences, maintaining that the well-trained mathematician should know about the stars and planets, and how to work with chemical apparatus, and how to make maps and navigate a ship. At the time, mathematics was mostly the province of “mathematical practitioners,” artisans who needed mathematical knowledge to engrave the dials on an astrolabe or to make a clock. Natural philosophers, what we call scientists, generally avoided mathematics, as had their fountainhead, Aristotle. Mathematics came into science through the side door, and the gate-keepers were the likes of John Dee and his cohorts in natural magic. They deserve more respect than they are commonly accorded.

Last summer, in this space, we ran a profile of John Day, the publisher of Dee’s Euclid, who introduced pop-up figures into geometry. The portrait of Day in that work is sometimes confused for that of Dee, especially since they shared the same initials: “I.D.” There is a true portrait of Dee in the Ashmolean Museum at Oxford (first image).

Dr. William B. Ashworth, Jr., Consultant for the History of Science, Linda Hall Library and Associate Professor, Department of History, University of Missouri-Kansas City. Comments or corrections are welcome; please direct to