Golf fans these days live in what amounts to a twilight era of one-man rule: that of Tiger Woods, still clinging to the throne even as usurpers rise up around him. Before Woods there was a duumvirate at the top of golf — Jack Nicklaus and Arnold Palmer — and before them there was the triumvirate of James Dodson’s new book: Sam Snead, Byron Nelson and Ben Hogan. More at the top is better, it turns out, or at least more interesting, and Dodson’s book evokes an era when golf was more vivid and less corporate than it seems now.

Hogan died in 1997; Snead in 2002; and Nelson in 2006, by which time he had been retired from competitive golf for 60 years. Most of their contemporaries are gone, and there aren’t too many people anymore who actually saw them swing except at the Masters, where for a couple of decades, until Snead accidentally beaned a spectator, he and Nelson used to whack ceremonial drives off the first tee. Hogan, once he retired, was too proud to take his game out in public and ended his days practicing by himself.

Dodson, who wrote a very good authorized biography of Hogan, has based “American Triumvirate” on interviews (including ones with Snead and Nelson), contemporary accounts and oral histories like Al Barkow’s essential “Gettin’ to the Dance Floor,” and manages to reanimate his chosen three. His book makes a convincing case that Snead, Nelson and Hogan really did usher in the modern era of golf — because of the quality of their play and the dramatic nature of their rivalry — and it’s also a fascinating biographical account of three gifted, unusual men who grew up in the Depression, discovered that they excelled at a once snooty game that was beginning to grab the popular imagination, and found wealth and fame in the vastly different America that came in the wake of the war.

In telling this part of the story, Dodson (who also repeats himself occasionally and doesn’t always steer clear of cliché) missteps a little, cramming in some potted social history far less revealing than the actual lives of these golfers. All three were born 100 years ago, in 1912, when golf was still catching on in this country: first Nelson and then at three-month intervals, Snead and Hogan. All were from the South: Snead grew up in the mountains of Virginia, Nelson and Hogan within a couple of miles of each other near Fort Worth. All were poor, and were introduced to golf when they turned up at the caddie yard (Nelson and Hogan at the very same club, Glen Garden, a nine-holer with sand greens) hoping to make some pocket money. And all three paid close attention to the world of the well-to-do they glimpsed from the practice tee or the pro shop.