Like life itself, history usually fails to be clear cut. Especially when examined up close, the past seldom divides into decisive periods with precise beginnings and endings. That’s one of the lessons in John Fleming’s enormously enjoyable study The Dark Side of the Enlightenment. The European Enlightenment is thought of as a triumph of science and reason over medieval superstition, and yet science and the occult were closely intertwined; the Enlightenment saw a proliferation of secret societies and wonder workers spreading their messages through the nascent mass media of newspapers and pamphlets. Fleming is a wonderfully informative and erudite guide down the darker, and more interesting, paths of cultural history.