Ralph Thomas -- elder brother of director Gerald Thomas -- was educated at Middlesex University College and entered the movie industry as a clapper boy in 1932. By 1934, he had advanced to assistant editor but gave up the picture business to pursue a career in journalism that lasted until World War II, during which he served with the Ninth Lancers. After World War II, he returned to motion pictures as the head of the trailer department for the Rank Organisation. He became a director soon after, and established himself as an efficient and occasionally inspired filmmaker whose best work cut across genres -- among his finest films is the Hitchcockian thriller The Clouded Yellow (1951), which in many ways anticipated the plot line of the television series The Equalizer, with Trevor Howard portraying a former British intelligence agent forced out of the service for some unknown indiscretion, who hires himself out as an assistant to a scientist, only to find himself helping the man's niece (Jean Simmons) flee the police from a murder charge, using his former agent's skills to help them both elude capture. He found even greater success, however, as a maker of comedies, most notably the Doctor in the House series starring Dirk Bogarde, beginning with the film of that title in 1954 and continuing through three more films (with Michael Craig taking over Bogarde's part). Thomas also distinguished himself as an action film director with Above Us the Waves, a re-enactment of an actual World War II British sabotage mission against the German battleship Tirpitz, starring John Mills. At the end of the '50s, he also directed respectable if unexceptional remakes of two '30s film classics, A Tale of Two Cities starring Bogarde, and The Thirty-Nine Steps with Kenneth More. During the '60s, Thomas also tried his hand successfully at topical filmmaking (The High Bright Sun aka McGuire Go Home, about the strife on the island of Cyprus) and even entered the James Bond-based spy thriller fray late in the '60s with two modern-day Bulldog Drummond adaptations, Deadlier Than the Male and Some Girls Do, both starring Richard Johnson as the updated Hugh "Bulldog" Drummond. His 1971 science fiction film Quest for Love, based on a short story by John Wyndham (best remembered as the author of Day of the Triffids and The Midwich Cuckoos, both of which were made into major science fiction movies), about a scientist who passes between two parallel Earths, was one of the most intelligent films in its genre at the time, and also features one of the finest performances ever given by Joan Collins. Alas, Thomas' career slowed down drastically following his unsuccessful sex satire Percy (1970), about the world's first penis transplant (a film best remembered today for having been scored by Ray Davies and the Kinks) and its even more dire sequel, Percy's Progress.