Exceptional theatrical publicity shot featuring Peter Cushing (Dr. Robert Knox), pictured here wearing a top hat, black gloves and trench coat while holding his silver walking stick.

The Flesh and the Fiends (US title Mania) is a 1960 British horror film directed by John Gilling. It stars Peter Cushing as 19th-century medical doctor Robert Knox, who purchases human corpses for research from a murderous pair named Burke and Hare (George Rose and Donald Pleasence). The film is based on the true case of Burke and Hare, who murdered at least 16 people in 1828 Edinburgh, Scotland and sold their bodies for anatomical research. Writer/ Producer John Gilling, along with producers Robert S. Baker and Monty Berman of Tempean Films, formed Triad Productions specifically to make the film.

It was the first horror movie to feature newly minted horror star Peter Cushing that was not produced by Hammer Films. Gilling had previously written a film about Burke and Hare entitled The Greed of William Hart in 1948. At that time, however, the British Board of Film Censors demanded that all references to the real-life killers were removed, and so Gilling was forced to rename the killers and several other key characters. The Flesh and the Fiends restores the correct historical names and begins with the text: "this is a story of vice and murder. We make no apologies to the dead. It is all true."

However, the filmmakers were still not permitted to use Burke and Hare's name in the title, and chief censor John Trevelyan called Baker to his office to discuss his concerns about several "potentially offensive sequences," though the film was ultimately passed uncut with an "X" rating. To minimize any similarities to Gilling's previous film (and to the then un-produced script on the same subject by Dylan Thomas, which would eventually be produced in 1985 as The Doctor and the Devils), the film's producers brought in Leon Griffiths to rewrite Gilling's original screenplay.

In his autobiography, Peter Cushing; who had been catapulted to fame by his portrayal of Victor Frankenstein in 1957's The Curse of Frankenstein, compared the role of Dr. Knox to his most famous character: "Now it seemed to me that Knox and 'Frankenstein' had a lot in common. The minds of these exceptional men were driven by a single desire: to inquire into the unknown. Ahead of their time, like most great scientists, their work and motives were misunderstood."

The drooping left eye which Mr. Cushing uses in his performance (emphasized in many of the film's posters, though not in the American one) is accurate to the real Dr. Knox, who had his left eye destroyed and his face disfigured by smallpox he contracted as an infant. In recent years, it has enjoyed something of a stronger critical reappraisal as a cult film. Reviewing the 2001 DVD release by Image Entertainment, critic Glenn Erickson praised the acting as "first rate," and added, "The production values of The Flesh and the Fiends outshine the House of Hammer.... The film is lacking in outright grue and gore but the tone is perfect."