John Dee (July 13, 1527 – 1608 or 1609) was a noted British mathematician, astronomer, astrologer, geographer, occultist, and consultant to Queen Elizabeth I. He also devoted much of his life to alchemy, divination, and Hermetic philosophy. Dr. Dee (Or, Mr. Dee, as he left university before achieving his doctorate) straddled the worlds of science and magic just as they were becoming distinguishable. One of the most learned men of his time, he had lectured to crowded halls at the University of Paris when still in his early twenties.

He was an ardent promoter of mathematics, a respected astronomer and a leading expert in navigation, having trained many of those who would conduct England's voyages of discovery. (He coined the term "British Empire.") At the same time, he immersed himself deeply in magic and Hermetic philosophy, devoting the last third of his life almost exclusively to these pursuits.

For Dee, as with many of his contemporaries, these activities were not contradictory, but particular aspects of a consistent world-view. In 1564, Dee wrote the Hermetic work Monas Hieroglyphica ("The Hieroglyphic Monad"), an exhaustive Cabalistic interpretation of a glyph of his own design, meant to express the mystical unity of all creation. This work was highly valued by many of Dee's contemporaries, but the loss of the secret oral tradition of Dee's milieu makes the work difficult to interpret today.