In 1564, in the Flemish city of Antwerp, John Dee wrote a short book in twelve days. The Elizabethan scholar, an astronomer, mathematician and adviser to Queen Elizabeth, said the book was written in a fever of inspiration, in only twelve days, and meant for the emperor himself. It was printed that year under the title Monas Hieroglyphica , "The Hieroglyphic Monad." It has been called the most obscure book of the English Renaissance. Its subject is one picture, drawn with a compass and a ruler, and the claim that this single figure holds the key to the whole of nature. A Mathematician in an Age of Magic Dee was born in London in 1527 and studied at Cambridge, then in Louvain and Paris, where lectures on Euclid in 1550 drew crowds of students. Back in England, Dee built a library at Mortlake that became one of the largest in the country, advising navigators, writing on mathematics and casting horoscopes. Dee is said to have picked the date of Elizabeth's coronation. ...