Gene Autry rode and sang his way across the plains.

IN 1992, when he was 82, Gene Autry was the only show business figure to make Forbes magazine's annual list of the 400 richest Americans. By the time he died, six years later, the magazine estimated his wealth at $320 million, most of it derived from a chain of radio and television stations he had patiently acquired, as well as real estate, oil wells and, of course, his huge catalog of musical copyrights. He still had an aging, dwindling base of nostalgic fans, though he had not performed in public for something like three decades.

Autry deserves to be regarded as an important American figure — certainly a significant one in the history of Los Angeles. A new biography tells the story. Born to a shiftless father and a sickly mother near Tioga, Texas, Autry received a primitive education and became a telegrapher for the St. Louis-San Francisco railroad. It was a job he clung to even as he began warbling and wandering as the "Oklahoma Yodeling Cowboy." Entirely self-taught as a singer and guitar picker, Autry had a pleasant, unpretentious voice and manner, and his records and radio work brought him to the modest hinterlands of fame. The movie business called in 1934, when he made the first of his 92 B-movie westerns. Soon thereafter, he had a network radio show and a relentless schedule of public appearances, mostly with rodeos that he owned.

Here, a certain mystery — which is not entirely solved by Holly George-Warren in her devoted but not very venturesome biography, "Public Cowboy No. 1" — enters our story. Put simply, it is: How in the world did Gene Autry become the richest cowboy in human history?