Soon after atomic bombs exploded over Hiroshima and Nagasaki in 1945, MGM set out to make a movie studio chief Louis B. Mayer called "the most important story" he would ever film: a big budget dramatization of the Manhattan Project and the invention and use of the revolutionary new weapon.

Over at Paramount, Hal B. Wallis was ramping up his own film version. His screenwriter: the novelist Ayn Rand, who saw in physicist J. Robert Oppenheimer the model for a character she was sketching for Atlas Shrugged.

Greg Mitchell's The Beginning or the End chronicles the first efforts of American media and culture to process the Atomic Age. A movie that began as a cautionary tale inspired by atomic scientists aiming to warn the world against a nuclear arms race would be drained of all impact due to revisions and retakes ordered by President Truman and the military.

Mitchell has found his way into the lofty rooms, from Washington to California, where it happened, unearthing hundreds of letters and dozens of scripts that show how wise intentions were compromised in favor of defending the use of the bomb and the imperatives of postwar politics. As in his acclaimed Cold War true-life thriller The Tunnels, he exposes how our implacable American myth-making mechanisms distort our history.