That Horatio Alger Jr. was one of the most influential writers in American history is indisputable; his dozens of moralistic, uplifting novels were read by millions of youths in the late 19th and early 20th centuries, with an effect upon prevailing attitudes that was, if incalculable, indisputably large. Yet Alger himself has been almost entirely unknown to us, in substantial part because after his death his sister, acting upon his specific request, destroyed all of his private papers.

There was, according to Gary Scharnhorst and Jack Bales, a reason for this: Alger was desperately afraid that a biographer would discover the great shame of his life, his dismissal in 1866 from a Unitarian ministry in Massachusetts on uncontested charges of, as the congregation's report put it, "gross immorality and a most heinous crime, a crime of no less magnitude than the abominable and revolting crime of unnatural familiarity with boys, which is too revolting to think of in the most brutal of our race."

Small wonder Alger wanted no biography: The author of "Ragged Dick," "Tattered Tom" and "Ben the Luggage Boy" was a pederast. But biographies there nonetheless have been, five before this one -- and all of them, as Scharnhorst and Bales most convincingly argue, riddled with fabrications and lies. In fact the first, written by Herbert R. Mayes and published in 1928, was a deliberate hoax, intended as its author subsequently acknowledged to be "a delightful spoof" of the Alger mythology. Instead it was received quite soberly as the definitive word, and remained the principal source of information -- or, more accurately, misinformation -- about Alger.

So now it has fallen to Scharnhorst and Bales, who say they were encouraged in the task by Mayes, to set the record straight. This they seem to have done, in a slender but apparently authoritative biography that reports only what the evidence permits and that limits psychological speculation to what the evidence itself suggests. Because the evidence is relatively meager, "The Lost Life of Horatio Alger, Jr." does not pretend to be a full biography, and because there is a disproportionate amount of evidence about certain periods of Alger's life, notably his foreign and domestic travels, there is rather more about them than is perhaps really necessary. But the book is a nice piece of scholarship, done against considerable odds and done very well.

Alger, who was born in 1832, was the son of a somewhat feckless minister who moved around and about Massachusetts before finally setting in Marlborough. Young Horatio was a bright student who went to Harvard, where he was successful in class and seems to have been popular. He had literary ambitions, but after college had to settle for a number of rather ordinary jobs in teaching and journalism while serving his writer's apprenticeship on the side; this consisted mainly of writing treacly stories and patriotic doggerel for various newspapers and magazines.

It was not until after he had gone into the ministry and then suffered his humiliating exit from it that Alger at last found his calling. He fled to New York, where he developed a deeply sympathetic interest in the city's street boys and began to write inspirational fiction based on their lives. "He loved all boys," someone who knew him later observed, and this seems to have been true; he once wrote that "I have a natural liking for boys, which has made it easy for me to win their confidence and become intimately acquainted with them," and he thought boys were "natural," girls "artificial." The authors do not speculate as to whether these affections ever took overt homosexual form, but a sensible guess would seem to be that Alger had been so traumatized by the Massachusetts experience that any subsequent relationships were platonic.

In any event, his novels made him a success, though never rich; for much of his life he had to supplement his income from them with various endeavors. When he died in 1899 his estate was small, and his funeral went almost unnoticed. But he has lived on in American legend as the mythologist of capitalism, hard work and success. This mythology, Scharnhorst and Bales contend, is "unearned"; they believe that later generations of readers transformed Alger, the pious moralizer, into "a patriotic defender of the social and political status quo and erstwhile advocate of laissez-faire capitalism." This is a matter of interpretation, though it must be said that Scharnhorst and Bales make a strong case for reconsidering Alger's legacy as well as his life. In both regards, they have done him good service.