By its end, the reader "will have dipped into the various forms which magic has taken and is taking, and will have been introduced to some of the eminent dupes who believed in it and the successful charlatans and fanatics who hoodwinked them."

In fact, his "main quarrel with the book" is that "it is presented almost wholly as a ballet of dupes and charlatans;" he considers the authors "a little too unyielding in their criteria for distinguishing between scientists and charlatans," adding "I have the feeling that the de Camps, rationalists themselves, simply could not generate the same kind of understanding interest in this behavior that they showed in their examination of ancient ruins (archeological and archaeologists), or that Sprague brought to his classic study of lost continents."

"[5] Judith Merril, writing in The Magazine of Fantasy and Science Fiction, calls the book "the usual meticulous de Camp work--or doubly so, since this one is co-authored by L. Sprague and Catherine C." She assesses it as "a fascinating study of magic, in history and practice.

Elements Leiber cited with approval included the de Camps' examination of "the primitive foundations of sorcery," the "historical development and ... modern instances of astrology, consultation of oracles, prophecy, witchcraft, alchemy, numerology, belief in fairyland, mesmerism (dubious parent of hypnotism, spiritualism, and theosophy."

He commended them for their "sturdy moral stand" against occult charlatans and the mindsets of their "natural prey"—in the words of the authors, "people who want knowledge without study, health without self-discipline, wealth without work, safety without precautions, and, in general, happiness without earning it.