Jonathan Franzen on collision of youthful idealism and reality in "Purity"

In Jonathan Franzen's new novel, "Purity," there is sex, infidelity, murder, lies -- and humor.

"I think of myself as a funny writer. Not everyone sees it that way, but people making mistakes are funny," Franzen said Thursday on "CBS This Morning." "And people making mistakes when they're young and then living with the consequences of their mistakes -- and it's a big book, so we follow some of the characters over 25, 30 years -- see what happens when that youthful idealism encounters reality. That can be a comic collision. People who are not in touch with reality I find funny."

"Purity" follows five characters, one of whom is Pip Tyler, a Californian girl in her mid-20s who has a reclusive, "nutty" mother and has no idea who her father is. Tyler gets recruited for an internship with The Sunlight Project in South Africa, which competes with WikiLeaks and is led by a German peace activist who rose to fame after the fall of the Berlin Wall.

Franzen, who has sold millions of books and won the National Book Award for "The Corrections," said he was always interested in the culture of surveillance in East Germany, which comes into play in "Purity."

"I wanted to tell a story in which the Stasi might not be an enemy, but the friend one of the characters," he said.

Franzen described the characters as "interesting and troubled."

"And you get to more interesting places with a piece of fiction when you have people who are not normal but kind of at the extreme margin, and you get to these dramatic and revealing places with extreme people," Franzen said.