If you care about plagiarism, you might find this entire article of interest. It's another case of "do as I say, not as I do," and I find it a tad dishonest. But what do I know? It happens in "commercial" fiction all the time, as the article points out.
Hat tip to The Little Professor for the link.
02138 � A Million Little Writers: "In September 2004, Charles Ogletree, a professor at Harvard Law School, found himself having to admit that his latest book, All Deliberate Speed, contained six paragraphs lifted verbatim from a book by Yale professor Jack Balkin, What “Brown v. Board of Education” Should Have Said. Equally surprising was the fact that Ogletree hadn’t known about the plagiarism, which occurred in a passage about the history of desegregation efforts, until he was told of it by Balkin himself."