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.