that episodes would be shot using the single-camera setup, giving the production greater flexibility. The use of film production and the single-camera production style allowed more sophisticated visuals and camera angles, and more outdoor location shots, all of which greatly improved the look of the series. As was standard on British television filmed production through the 1960s, all location work on Series 4 was shot mute, with the soundtrack created in post-production. Dialogue scenes were filmed in the studio, leading to some jumps between location and studio footage. New female partner Mrs Emma Peel (Diana Rigg) debuted in October 1965. The name of the character derived from a comment by writers, during development, that they wanted a character with "man appeal". In an early attempt to incorporate this concept into the character's name, she was called "Samantha Peel", shortened to the awkward "Mantha Peel". Eventually, the writers began referring to the idea by the verbal shorthand "M. Appeal", which gave rise to the character's ultimate name. Emma Peel, whose husband went missing while flying over the Amazon, retained the self-assuredness of Gale, combined with superior fighting skills, intelligence and a contemporary fashion sense. After more than 60 actresses had been auditioned, the first choice to play the role was Elizabeth Shepherd. However, after filming one and a half episodes (the pilot, "The Town of No Return", and part of "The Murder Market"), Shepherd was released. Her on-screen personality was deemed less interesting than that of Blackman's Gale, and it was decided that she was not right for the role. Another 20 actresses were auditioned before the show's casting director, Dodo Watts, suggested that producers Brian Clemens and Albert Fennell check out a televised drama featuring the relatively unknown Rigg. (She had earlier guested in an episode of The Sentimental Agent that Clemens had written.) Rigg's screen test with Macnee showed that the two immediately worked well together. A prologue was added to the beginning of all the fourth-series episodes for the American broadcasts. This was to clarify some initial confusion audiences had regarding the characters and their mission. In the opener, a waiter holding a champagne bottle falls dead onto a human-sized chessboard, a dagger protruding from a target on his back. Steed and Mrs Peel (dressed in her trademark leather catsuit) walk up to the body as the voice-over explains: "Extraordinary crimes against the people, and the state, have