By now, every candidate in the 2008 election has published at least one book, from Obama on down to Biden. The former has, in fact, written two memoirs — The Audacity of Hope and Dreams of My Father — both of which were runaway best sellers. Why? Jon Meacham, the managing editor of Newsweek, argues that the senator’s compelling life story has made them so popular.

Says Meacham, “One of the most ancient devices in presidential politics is to sell one’s life journey as the qualification for high office, whether it’s Lincoln in the log cabin or Andrew Jackson standing up as a 14-year-old to the British and having the British officer hit him in the head with a sword, and it was, I think, very astute of Obama to use his own life in that way.”

Books as a campaign tool began in earnest with Jimmy Carter during the 1976 election, when he published Why Not the Best? “It’s a way of getting his vision of the country out,” Meacham told NPR. “And since then, it’s become a kind of course requirement for a presidential candidate to publish something. How many people read them I think is a very open question.”

Read the article and listen to the full interview.