Mark Harris’s subject is the war service from 1942 to 1945 of five distinguished directors: John Ford, Frank Capra, George Stevens, John Huston and William Wyler. Like those other authentic war heroes James Stewart, David Niven and Clark Gable, these men all volunteered for the armed services, taking a massive pay cut and the risk that, if the war dragged on, they would become Hollywood’s forgotten men.

Harris’s approach is novel, but the book suffers from an uncertainty of focus. It is never quite clear what moral or message he intends us to draw from his narrative or who the target readership is. Movie buffs who have read the biographies of the five men will know 95 per cent of the story and the anecdotes already. For those who have not, the arcana will doubtless elicit a head-scratching response. But Harris’s work is pleasingly unpretentious and well served by a strictly chronological narrative.

John Ford is best known as the director of classic westerns (The Searchers,