wife, Sylvia, had written a 194-page treatment long before the initial meeting with Kanter. Although they had originally planned it as a one-hour drama for Associated Television, Sylvia thought the premise "too good for a television play" and suggested developing it as a feature film instead. John Read, the Andersons' business partner, suggested the title "Doppelgänger". According to Gerry, this term "means 'a copy of oneself', and the legend goes that if you meet your doppelganger, it is the point of your death. Following that legend, clearly, I had to steer the film so that I could end it illustrating the meaning of that word". Responding to claims that the tone was overly "dark", Anderson said that he wanted the film to have an interesting premise. Kanter was dissatisfied with the script, so Anderson hired Donald James to improve the characterisation. James's revisions included substantial changes to the parts set on the mirror Earth, essentially causing the characters of Ross and Kane to switch roles: in the original script, the Dove crash resulted in Ross being blinded; Kane survived, only for EUROSEC to declare him insane. A structural flaw in Doppelgänger caused it to burn up in the atmosphere with Kane trapped inside, and the film ended with Kane's wife, Jason Webb, and the Rosses attending Kane's funeral. Despite James's efforts, Kanter remained unenthusiastic. However, he agreed to finance the film provided that the Andersons chose a director who met with his approval. Gerry's first choice had been Century 21 employee David Lane, who had directed the puppet films Thunderbirds Are Go (1966) and Thunderbird 6 (1968), but Kanter wanted a veteran director with mainstream experience. After several weeks of searching, the Andersons hired Robert Parrish, who had been one of the directors on Casino Royale (1967). According to Gerry, Parrish "told us he loved the script and said it would be an honour to work with us. Jay Kanter gave Bob the thumbs up and we were in business". Anderson also said that while the poor response to Casino Royale may have raised questions about Parrish's ability, Doppelgänger could not have been made without him: "It wasn't a question of, 'Will we get on with him?' or, 'Is he the right man?' He was a name director, so we signed him up immediately". Casting Leading the cast was Roy Thinnes as Colonel Glenn Ross of NASA. Gerry Anderson cast