The Keep is a 1983 dark fantasy horror film written and directed by Michael Mann and starring Scott Glenn, Gabriel Byrne, Jürgen Prochnow, Alberta Watson and Ian McKellen. It is an adaptation of the 1981 novel of the same title by F. Paul Wilson. The musical score was composed by Tangerine Dream. Filmed in Wales and at Shepperton Studios during the autumn of 1982, The Keep had a troubled production and suffered numerous cuts that reduced the original runtime by over 100 minutes. It was released by Paramount Pictures on December 16, 1983 to mixed reviews, but has developed a cult following.