On CSPAN's Book TV Sunday, David Maraniss revealed a photo of Obama's pot smoking 'Choom Gang' and shared some of the information he learned about while writing his book.

"The Choom Gang, that's what they did," Marannis said, revealing the photo and talking about the gang's practice of "total absorption" of marijuana smoke while sitting in a car. "That was part of his existence during that period."

Video below: