Crop Circles: ISBN 978-1-60152-103-3 / eBook: 978-1-60152-424-9
Werewolves: ISBN 978-1-60152-097-5 / eBook: 978-1-60152-420-1
Booklist, April 1, 2010

Angels, King Arthur, and unicorns have all been subject to the Mysterious & Unknown series, which continues to put its magnifying glass to humankind’s biggest question marks. Although the books may look standard at first glance, they are surprisingly exhaustive. Crop Circles is a perfect example—how much is there to say about some crushed corn stalks? Plenty. Kallen reaches back to a 1678 account of a “Mowing-Devil” before considering numerous potential culprits: plasma vortexes, psychokinesis, UFOs, the military, and even wallabies stoned on opium. Equal time is spent between cereologists (those who study these formations) and plain old hoaxsters—and both are equally interesting. Breakout summaries and quotes enliven the layout, and though illustrations of enticingly described evidence are sometimes omitted, there is still plenty of creepy stuff to scrutinize. Extensive notes and indexes conclude.
—Daniel Kraus