First published 1941.
Williams himself states by way of introduction, These pages must stand for what they are—a brief account of the history in Christian times of that perverted way of the soul which we call magic, or (on a lower level) witchcraft, and with the reaction against it. That they tend to deal more with the lower level than with any nobler dream is inevitable.
This was a painful book to read, as any sane and even-handed history of the times would have to be. As another reader stated, it is neither hysteria nor propaganda, but a carefully written history by a master thinker, researcher and writer.
Highly recommend, but be prepared for a tough slog. Do not expect a Harry Potter prequel. The evils and perversions committed by both those purporting and those prosecuting witchcraft were real and terrible. Yet there were bright lights as well, and Williams gives them due credit, as partial and imperfect as they may have been.