Marvel at the making of this movie

In Search of The Third Man by Charles Drazin (Methuen, £12.99)

In Search of The Third Man by Charles Drazin (Methuen, £12.99)

"I TOO once met a girl in Central Park, but it is not much to remember," says the narrator of Walker Percy's novel The Moviegoer. "What I remember is the time John Wayne killed three men with a carbine as he was falling to the dusty street in Stagecoach, and the time the kitten found Orson Welles in the doorway in The Third Man."

Charles Drazin's admiring, sharp-eyed study overlooks this resonant memory but notes that the cat was filmed in Shepperton, rather than Vienna, and was one of several dragooned into service. From a composite of those obstinate felines came that sequence with Harry Lime's face lit up in the doorway. The rest we know - and watch time and again with the same surprise.

To say that Drazin also points out that Lime's face would hardly have been illuminated by a 60-watt bulb from above risks making him appear a pedant. Yet his eye for fascinating detail never supplants the poetry of the movie. We marvel all the more at the serendipitous way its creative spirits were brought together.

Drazin's 200 nimble pages convey more facts than many a more hefty book. Without the aridity of "film studies", he sets out the machinations behind the movie, which were as fraught and duplicitous as anything on the screen.

It is well known that Graham Greene had long entertained the idea of a man apparently returned from the dead. The theme was given fresh impetus by his one-time bete noire Alexander Korda, who had a Lime-like desire to duck exchange controls by using foreign revenues to film the four-power control of post-war Vienna. Carol Reed, long admired by Greene, took up the subject, but the whole scheme was almost sabotaged by David Selznick, whose interference led to a torrent of memos and a wretched re-editing of the movie for America.Lacking the rancour of some Greene chroniclers, Drazin eschews black and white in favour of shades of grey worthy of all those Vienna (or Shepperton) streets caught so well by the cinematographer Robert Krasker. One of those shades is the revelation that not all of the film - and not the final scene - was photographed by Krasker.

Greene graciously credited Reed with Anna's long walk past Joseph Cotten and out of shot. In fact, although Selznick is reviled in various accounts of the movie and did make absurd suggestions, a memo notes that he said at a meeting "that it was a great pity that at the end of the story Rolly [the original name for Holly Martins, played by Cotten] and the girl Anna should finish together; we should go from the cemetery scene to Anna going away by herself. Selznick felt this very strongly, that Anna's love for Harry Lime should be fatal."

Drazin points out that re-emergence from the grave figures several times in Greene's work. He is alert to Greene's humour and mischief; happily, he is not waylaid by conspiracy theories but realises that ideas - such as the penicillin racket - are not one man's province. No script is sacrosanct; it is often polished up by others. Welles's own cuckoo-clock speech derives from a lecture by Whistler. Drazin digs up the playwright Jerome Chodorov, who calls his two days' work on the film his best assignment. He only regrets that nobody believes him and that, by overlooking advice to spend the money on a Frans Hals that was going cheap, he failed to become a millionaire.

Drazin treats soberly the question of how much in the movie was inspired by the double agent Kim Philby. He's sure the answer lies in Greene's grave. Chodorov calls Carol Reed "a strange duck" - and the movie's guiding force.

Unlike those directors who know only movies, Reed foraged about. He tracked down Anton Karas, first heard at a crowded welcome party where the host's wife could not recall the departed zither player's name. British Lion's chairman later wrote: "I think you've a big success there. But please take off the banjo."

That "banjo" quickly sold half a million copies. Drazin does not mention the Third Man board game (Greene owned one) and recurrent threats to remake the movie.

Perhaps Selznick's shade is currently at work with digital technology for a version with some of those stars he suggested - Cary Grant, Noel Coward and Ralph Richardson. Which would surely drive Walker Percy's moviegoer into Central Park.