Not only do historians sometimes get it wrong, but they tend to compound their errors by backing up one another. Such is the message of T.J. Stiles' groundbreaking biography, "The First Tycoon: The Epic Life of Cornelius Vanderbilt" (Alfred A. Knopf, 719 pages, $37.50), which overturns generations of scholarship depicting Cornelius Vanderbilt (1794-1877) as a ruthless steamship entrepreneur and railroad robber baron, a man of such authority that early on he earned the honorific "Commodore" without having served a day in the U.S. Navy.

To be sure, the hard-driving Vanderbilt undercut rivals and drove competitors out of the marketplace, but more often than not he was responding to the nefarious ploys of state legislators and other government officials who interfered with free trade, content to grant monopolies as long as they were paid off. Not only did Vanderbilt have a hand in breaking up the sweetheart deals of New York's aristocratic clan, the Livingstones, but his persistence eventually led to Justice Marshall's famous Supreme Court majority opinion prohibiting states from limiting interstate commerce.

Relying too heavily on a 19th-century press that saw mostly villainy in Vanderbilt's steadily increasing fortune and influence, historians have repeated the standard story rather than thoroughly researching the background of the Commodore's business deals. Stiles, born in Foley, Minn., and educated at Carleton College in Northfield, shows that Vanderbilt was often driven by speculators who forced him into the stock market -- usually, however, to buy up stock in his own concerns so as to stave off Wall Street panics.

A patriot, Vanderbilt put his ships into the service of the Union during the Civil War and did not expect compensation. Vanderbilt fares far better in Stiles' book than similar figures such as J.P. Morgan and Jay Gould, although the latter has been accorded a rather remarkable rehabilitation in a recent biography by Edward J. Renahan Jr.

It is largely due to figures like Vanderbilt that the country jettisoned a hierarchical culture of deference and mercantilism for all-out individualism and capitalism. Vanderbilt's contemporaries hardly saw the man and his mettle, so bedeviled were they by what seemed like capitalism gone amok. In fact, as Stiles shows, the picture was far more complex, with Vanderbilt playing the role of a radical overturning the fiefdoms of America's privileged class.

Stiles is attuned to the ironies of history: By the time Vanderbilt died, his buccaneering capitalism had become synonymous with conservative free-market politics.

Carl Rollyson is a biographer and journalism professor at Baruch College, City University of New York.