According to William Goldman, in his book Adventures in the Screen Trade (p227), when Peter Sellers was once asked whether he would make any changes to his life if he had the opportunity to do it all over again, Sellers replied he'd do "everything exactly the same, with the exception of watching The Magus (1968)".
Sir Michael Caine lists this, along with The Swarm (1978) and Ashanti (1979), as one of the worst movies he ever made. This is mainly down to the fact that no one, least of all the audience, knew what it was about.
A critical and commercial disaster, Screenwriter John Fowles laid most of the blame at the feet of Director Guy Green (despite Fowles having penned the screenplay). Fowles vowed never to write another screenplay after this. The only subsequent adaptation of any of his works, was Karel Reisz's The French Lieutenant's Woman (1981), which was adapted by Harold Pinter.
The train, seen at nighttime, below the hotel window is supposedly in Athens, but is actually the Palma-to-Soller train in Majorca/Mallorca.
John Fowles insisted on writing the screenplay, having been so disappointed with William Wyler's adaptation of his novel The Collector (1965).
Second movie in two years shot on a Greek island for Candice Bergen, after Michael Cacoyannis' The Day the Fish Came Out (1967).
Though this movie was set in Greece, the majority of it was filmed in Majorca, Spain.
Candice Bergen said in an interview: "I didn't know what to do, and nobody told me. I couldn't put together the semblance of a performance."
The cove where most of this movie takes place was called Cala El Mago (cove of The Magus) by the locals after the end of filming.
John Fowles was not happy with the filmed versions of his earlier novels "The Collector" (1963) and "The Magus" (1965) Both of these works had previously been filmed, prior to the publishing of Fowles' third novel "The French Lieutenant's Woman" (1969). So Fowles insisted on selecting the director of The French Lieutenant's Woman (1981), and his first choice, Karel Reisz, became the movie's director.
This movie was shot in Spain, the Majorcan location of Andritx, not far from Calvià, close enough to Portals. The beach is still called nowadays "El Mago" because of that filming.