John Day, an English printer, died July 23, 1584, at an age of about 62. In the muggle world, Day is best known as the printer of John Foxe’s Actes and Monuments [of English Protestant Martyrs] (1563), one of the most successful publications of the English Protestant Reformation. But in the wizard world, Day is renowned as the publisher of Elements of geometrie of the most auncient philosopher Euclide (1570), the first edition in English of this geometrical classic. The translation was the work of Henry Billingsley, and the book contains a long preface by John Dee, a hymn to natural magic, now quite famous in its own right, so the book is often referred to as the Dee Euclid or the Billingsley/Dee Euclid. It could just as well be called Day’s Euclid, since much of the attractiveness of the book comes from its type fonts, woodcuts, and layout. Its most striking novelty is a set of pop-up geometrical figures in the section that deals with three-dimensional geometry; we show two sample pages above. We have Day’s Euclid in our History of Science Collection, complete with all pop-ups.

The 1570 Euclid is also unusual in having a portrait at the end, which depicts, not Euclid or Dee or Billingsley, but the printer, John Day. This provides yet another reason why we should refer to the book as Day’s Euclid.

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