"Scientist, mathematician, and court astrologer to Queen Elizabeth I, John Dee is also one of the sixteenth century's most renowned alchemists, driven by a passion to fathom the elemental secrets of the cosmos. But when his reckless assistant, Edward Kelley, succeeds in using a crystal sphere to summon angels, Dee is catapulted into an awesome struggle that may extinguish the light of reason forever." "One of the spirits invoked is a cunning demon...