In his Introduction, Mayes writes that his book, on first publication:
was not accepted for what it was: a deliberate, complete fabrication, with virtually no scintilla of basis in fact. Any word of truth in it got in unwittingly. I made it up out of nothing. Most of the few facts I uncovered were intentionally distorted. But the book was regarded then, with no known exceptions, as a genuine biography. (ii-iii)
Wow. As a result, as Bales writes in the Afterword:
The greatest obstacle to studying the life of Horatio Alger, Jr. is the fact that most of what has been published about the author since Herbert R. Mayes’ work appeared in 1928 is fictitious. (242)
Not even the debunking that has occurred, starting in the early 1970s, has managed to derail the misinformation:
But writers, I am sure, will continue to perpetuate these absurd myths. In 1974 I was asked to write a short piece on the Mayes book for the Journal of Popular Culture [Jack Bales, “Herbert R. Mayes and Horatio Alger, Jr.; Or the Story of a Unique Literary Hoax,” Journal of Popular Culture, 8(Fall, 1974), 317-319]. One can imagine my disgust when recently in the same journal I read an article on Alger based almost entirely on Mayes’ fiction [Eric Monkkonen, “Socializing the New Urbanites: Horatio Alger Jr.s’s Guidebooks,” Journal of Popular Culture 11 (Summer, 1977), 77-87]. It is obvious that the fallacies which have been so repeated and accepted for five decades will be related again and again in future years. (244-245)
The elegance of the internet is that it can stop such things. The absurdity of the internet is that it perpetuates such things.
The determination of fact or fiction, then, is the responsibility of each of us. Our research tools alone won’t suffice. Only care, learning, and constant attention can do that.