A cast of master mechanics ensnared by machines

There's a good case for naming Fritz Lang as the single most influential film-maker of the 20th century. One of his chief disciples was Alfred Hitchcock, who watched him at work at the UFA studios at Babelsberg before embarking on his own career.

Furthermore, Lang not only influenced virtually every practitioner of classic 1940s film noir - Robert Siodmak, Edgar Ulmer, Otto Preminger, Billy Wilder et al - but can be personally credited with importing the noir style, with its encroaching shadows and sense of inexorable fate, into American cinema.

Lang's influence extended well beyond matters of style. You Only Live Once laid down the template for every "outlaw couple on the run" movie from They Live by Night to Thelma and Louise , and The Big Heat did as much for the maverick cop cycle. The figure of Dr Mabuse spawned countless sinister master criminals; the towering vision of the future in Metropolis would be recycled in science-fiction movies for decades, while the creation of the evil robot, all spouting gothic vapours and fizzing electric arcs, was taken over wholesale for James Whale's Frankenstein and passed into the standard iconography of the horror movie; even today few serial-killer films can escape a nod to the sad, shambling ghost of Peter Lorre in M .

All the more surprising, then, that critical studies of Lang's work have been so thin on the ground. Recently Patrick McGilligan gave us an exhaustively researched, if often crassly sensationalist biography, Fritz Lang: The Nature of the Beast , but no new English-language critical account has appeared since the late 1970s. Tom Gunning's book is long overdue and his approach is a good deal more sophisticated than simple auteurism; he proposes Lang as an integral part of his own films at once within them and outside them. "The search for the author," he observes, "takes place in a labyrinth in which at times even the fim director himself may have lost his way... I am claiming that Fritz Lang as author in some sense merged with his films."

Central to Gunning's thesis is the concept of the destiny-machine, an element within the plot that entraps Lang's characters and "determines the environment in which (they) struggle, serving in most cases as an obstacle". The destiny-machine is not necessarily mechanical, although it often works its effect through machines. In the early German thrillers, such as Der Spione and the Mabuse films, it expands to take in the communication systems of a whole city; in the mythic world of Die Nibelungen it is the combination of factors, natural and supernatural, that lead to Siegfried's fatal vulnerability; while in a Hollywood noir thriller like Scarlet Street , Gunning sees it in the workings of desire on the psychology of the henpecked clerk played by Edward G. Robinson. He also detects its operation in Lang's own life, as in the often-cited, and possibly apocryphal, interview when Goebbels asked Lang to take over the Nazi film industry. "Outside the window there was a big clock, and the hands went slowly round," as Lang loved to relate. Master criminals - Mabuse, the mob bosses of The Big Heat , or indeed the Nazis - may believe they control the machine, but they invariably find themselves trapped by it in the end.

Gunning sees the destiny-machine as closely linked to Lang's vision of modern urban life, in which "objects and the relations between themI take on a will of their own". This view of Lang's cinema as essentially paranoid can seem over-schematic, and Gunning tends to skim over those films - such as the westerns - that do not fit neatly into his thesis. He also dismisses the wartime anti-Nazi thrillers, including Man Hunt and Ministry of Fear , as "less accomplished works", although the woefully inept You and Me gets its own chapter.

Even so, and despite Gunning's occasional lapses into sophomoric prose - "What a hoot this film is!" - this is a searching, stimulating and perceptive account of Lang's oeuvre. Lang's admirers may take issue, but they will almost certainly want to re-watch the films in the light of Gunning's analysis.

Philip Kemp is a freelance writer and film historian.