Claim: Night of the Grizzlies, written by Jack Olsen, was published in 1969 and was first released only in hardcover.
Evidence: Night of the Grizzlies (1969) is a book by Jack Olsen which details events surrounding the night of August 13, 1967, when two young women were separately attacked and killed in Glacier National Park, Montana, by grizzly bears. June 1, 1969 — (1969). (1st, hardback ed.). G. P. Putnam's Sons. ISBN 0399105824.