The Ghostbusters concept was inspired by Dan Aykroyd's fascination with the paranormal. His father wrote the book A History of Ghosts. Aykroyd conceived Ghostbusters as a vehicle for himself and his friend and fellow Saturday Night Live alumnus John Belushi. Aykroyd also saw Ghostbusters as an opportunity to modernize the ghost films The Ghost Breakers (1940) and Ghost Chasers (1951). Around 1982, Ivan Reitman, along with Joe Medjuck and Michael C. Gross, had been working with Douglas Adams on an option for a film adaptation of Adams' The Hitchhiker's Guide to the Galaxy. As part of casting considerations for that film, Reitman suggested that Ford Prefect be played by an American actor to help connect the British work to overseas audiences, and recommended Aykroyd or Bill Murray. During this process, Aykroyd presented Reitman with his script, which he felt was a better film, and Medjuck, Gross and himself postponed development of Hitchhiker's Guide to develop this script.