Clark was born on November 27, 1946 and raised in
Canby, Minnesota, attending
South Dakota State University and
Moorhead State College. He has served as a writer, reporter, and editor for a number of magazines which cover UFOs and other paranormal subjects. He has been an editor of
Fate magazine and
International UFO Reporter. He also studied the UFO religion
Heaven's Gate prior to their 1997 mass suicide. Clark authored the multi-volume
The UFO Encyclopedia: The Phenomenon From The Beginning with its first edition published in 1992.
Library Journal stated in its review of
The UFO Encyclopedia that "A respected UFO authority provides a much-needed update of the [UFO] field with this new encyclopedia ... [it] is the most thorough treatment yet of this puzzling phenomenon ... the [encyclopedia] should be considered by larger public and academic libraries."
Choice: Current Reviews for Academic Libraries wrote that "the articles are factual and balanced, with neither a believer's nor a skeptic's viewpoint predominating", and that
The UFO Encyclopedia is "recommended for public libraries and undergraduate collections". In 1997 an abridged, one-volume edition of
The UFO Encyclopedia, entitled
The UFO Book: Encyclopedia of the Extraterrestrial, was published as a trade paperback. In 1998,
The UFO Book won the Benjamin Franklin Award in the Science/Environment category sponsored by the
Independent Book Publishers Association. In its review of his 1999 book
Cryptozoology A to Z,
Salon commented that Clark and co-author
Loren Coleman "show a touchingly supportive nature" for a subject often criticized for lack of scientific rigor.
Sunday Express combined its review of Clark's 2000 book,
Extraordinary Encounters, An Encyclopedia of Extraterrestrials and Otherworldly Beings with another similar book entitled
UFOs and Popular Culture by
James R. Lewis, calling both books "inexplicably entertaining" and commenting that they "manage throughout to maintain a healthy rationality and openmindedness, neither over-sceptical nor too ready to believe the claims of the UFOmongers." According to skeptical academic
Paul Kurtz, "Clark attacks skeptics for being closed-minded and dogmatic, yet he is easily impressed by questionable evidence." == Songwriting and music reviews ==