docsavage, here's an excerpt from Wikipedia --
Controversy
According to Eliot Weinberger, an American writer, essayist, editor and translator, Kosinski was not the author of The Painted Bird. Weinberger alleged in his 2000 book Karmic Traces that Kosinski was not fluent in English at the time of its writing.]
In a review of Jerzy Kosinski: A Biography by James Park Sloan, D. G. Myers, Associate Professor of English at Texas A&M University wrote "For years Kosinski passed off The Painted Bird as the true story of his own experience during the Holocaust. Long before writing it he regaled friends and dinner parties with macabre tales of a childhood spent in hiding among the Polish peasantry. Among those who were fascinated was Dorothy de Santillana, a senior editor at Houghton Mifflin, to whom Kosinski confided that he had a manuscript based on his experiences. Upon accepting the book for publication Santillana said, "It is my understanding that, fictional as the material may sound, it is straight autobiography." Although he backed away from this claim, Kosinski never wholly disavowed it."
M. A. Orthofer addressed Weinberger's assertion by saying: "Kosinski was, in many respects, a fake – possibly near as genuine a one as Weinberger could want. (One aspect of the best fakes is the lingering doubt that, possibly, there is some authenticity behind them – as is the case with Kosinski.) Kosinski famously liked to pretend he was someone he wasn't (as do many of the characters in his books), he occasionally published under a pseudonym, and, apparently, he plagiarized and forged left and right."