“…In the late 16th century, harnessing invisible spirit power was essentially the same kind of challenge as harnessing the invisible power of the wind. It was complicated, you needed to be highly educated, but if you could do it -rather like improving the technology of your ship’s sails, the world and its wealth were at your feet. Reaching the spirit realm however, was a touch more complicated than improving your ship.”

— New Science, Old Magic: Dr Dee’s Magical Mirror, A BBC radio program