CNN’s Peter Bergen reports that “Greg Mortenson, the high-profile advocate of girls’ education in Afghanistan and Pakistan, has been forced to defend his best-selling book Three Cups of Tea: One Man’s Mission to Fight Terrorism and Build Nations … One School at a Time, against charges that key stories in it are false.”

The bestselling book described Mortenson’s tale of getting lost climbing K2, the world’s second-highest peak, wandering away from his party and being rescued near death by Pakistani villagers in the village of Korphe, which inspired him to vow to return there to build a school for local girls. He also claimed to have been captured by the Taliban while trying to build schools in Pakistan.

“It’s a beautiful story, and it’s a lie,” Jon Krakauer, author of Into Thin Air and an early investor in Mrotenson’s efforts, told Steve Croft last night on CBS’s 60 Minutes, in a report that also investigated the shady finances of Mortenson’s charity that’s supposed to be building those schools. Croft, though, couldn’t get Mortenson to respond to his requests for an interview. So, in classic 60 Minutes fashion, Croft and a camera crew surprised Mortenson at a book signing. See what happens below in the 60 Minutes report.