Mystery Stalks the Prairie was published in 1976 by Keith Wolverton, a sheriff's deputy in Cascade County, Montana. He wrote the book to document numerous incidents of cattle mutilations and UFOs that he had investigated—and that could not be explained. Mystery became an instant classic—the first book to seriously examine cattle mutilations and related UFO reports. Nearly a half century later, Mystery remains the touchstone for similar investigations around the world. This updated and expanded edition features a new epilogue by Wolverton that describes his research since the publication of Mystery, and a 2016 interview with Wolverton and Pete Howard, another Montana sheriff who investigated cattle mutilations and UFOs and who witnessed “men in black” confiscate radar evidence of a UFO. An introduction to this edition by Joan Bird, author of Montana UFOs and Extraterrestrials, describes the enduring importance of Mystery; the status of UFO reports and cattle mutilations; and a little-known cattle mutilation on Montana's Blackfeet Indian Reservation in 1947 that included tribal elders describing earlier visits by extraterrestrials.