The Howling, based on the novel of the same name by Gary Brandner, was released in April, 1981. From IMDB: "Eye-popping special effects highlight an updated werewolf story. TV newswoman, Karen White, [played by Dee Wallace, who also played the mother in Cujo - kw] goes on a retreat after a traumatic incident with a serial killer. But is she really safe? And what should she fear more: regaining her memory or the creepy residents of "The Colony?"
Wolfen, based on the novel by Whitley Strieber, was released in July, 1981. It featured the best cast of the three movies, with Albert Finney, Edward James Olmos and Gregory Hines. From IMDB: " A city cop [Finney] is assigned to solve a bizarre set of violent murders where it appears that the victoms were killed by animals. In his pursuit he learns of an Indian legend about wolf spirits."
An American Werewolf in London, directed by John Landis (Animal House, The Blues Brothers) was released in August, 1981, and is the best-made of the three. It stars David Naughton ("I drink Dr. Pepper and I'm proud...") and Griffin Dunne, who plays Naughton's best friend and werewolf victim who keeps returning, in a hilariously ever-more-decomposing state. From IMDB: "Two American students are on a walking tour of England and are attacked by a Werewolf. One is killed, the other is mauled. The Werewolf is killed, but reverts to it's human form, and the townspeople are able to deny it's existence. The surviving student begins to have nightmares of hunting on 4 feet at first, but then finds that his friend and other recent victims appear to him, demanding that he find a way to die to release them from their curse, being trapped between worlds because of their unnatural death."
Even though they were released within months of each other, the three movies approach the traditional werewolf legend from different perspectives. If you ever want to have a "werewolf movie weekend," these three have to be on the schedule.