The Face of Fear
This is certainly an oddity. The book, The Face of Fear, is by Dean Koontz, an author infamous for his use of pseudonyms. Here, the British Sphere edition is published under his K.R. Dwyer pseudonym and the U.S. Ballantine edition uses his Brian Coffey pseudonym. Guess you could call it The Case of the Confused Author. Or maybe it's The Book No One Wanted.
Scans and Commentary are Courtesy of Fred Meyerriecks