Did Melville Borrow the Idea for 'Moby Dick'? [5min]

Literary historian Paul Collins found an odd ad in a rare first edition of Moby Dick author Herman Melville's 1849 novel Redburn. The ad was for another novel -- The Whale and His Captors -- by Rev. Henry Cheever. Collins and Scott Simon discuss the once-common practice of"improving upon" another author's work.