The original novel was published in 1967. It was a best seller in France before being released in the US. Film rights were bought by John Frankenheimer and Edward Lewis who set up the film at Columbia. Dalton Trumbo, who had just written
The Fixer for Frankenheimer, was signed to do the script. The film took two and a half years to make and was shot on location in Afghanistan, and in Spain (including
Caminito del Rey). According to director John Frankenheimer: It represents for me the first time I've been able to put together the two sides of my work – the spectacle like
Grand Prix or
The Train and the intimate kind of picture like
Birdman of Alcatraz or
Seven Days in May. For me it has a very contemporary meaning, which is why I did it. It's a man looking for himself, a theme that I've done over and over on TV and in movies. I do think that Dalton Trumbo is the best screenwriter we've got... Most of my films are about putting people under extreme pressure. Because my contention in life is that how you know people is how they respond to a crisis. ==Reception==