New book says Charles Manson used lessons in How to Win Friends and Influence PeopleYou have probably heard of a little book called “How to Win Friends and Influence People,” Dale Carnegie’s blockbuster. Well, so did Charles Manson. And according to a new book, the lessons in it were influential in shaping the cult-leader killer.

Jeff Guinn in his new book, “Manson: The Life and Times of Charles Manson,” details how Manson took classes centered around the book while in prison for car theft in 1957.

“It was critical in shaping how he manipulated people,” Guinn says in the book, according to Bloomberg Businesweek.

Of special interest was chapter seven and how to “let the other fellow feel that the idea is his”:

Former “Family” members Patricia Krenwinkel and Leslie Van Houten (who was denied her 20th bid for parole last month) both say Manson mastered the technique: Not only did he often solicit and praise his followers’ advice, he was careful to frame every killing as a Family decision.

Jackie Kellso, who runs Dale Carnegie courses in New York, says, “it’s a very hard concept to understand.” The notion of letting others take credit for your ideas goes against what most people are taught, she explains, yet “it’s fundamental to being a good leader.”

The article notes that it’s not odd for such training to be offered in prisons. But as Carnegie himself notes, it’s up to the individual how they use such training.

Unfortunately we know how Manson did.

Guinn’s book goes on sale August 6.