The original James Frey? Here's the author of Robinson Crusoe defending himself against the notion that he made any of it up:
"I Robinson Crusoe being at this Time in perfect and sound Mind and Memory, Thanks be to God therefore; do hereby declare, their Objection is an Invention scandalous in Design, and false in Fact; and do affirm, that the Story, though Allegorical, is also Historical; and that it is the beautiful representation of a Life of unexampled Misfortunes, and of a Variety not to be met with in the World, sincerely adapted to, and intended for the common Good of Mankind, and designed at first, as it is now farther apply'd, to the most serious Uses possible.
Farther, that there is a Man alive, and well known too, the Actions of whose Life are the just Subject of these Volumes, and to whom all or most Part of the Story most directly alludes, this may be depended upon for truth, and to this I set my Name."
More reflections here.