Two books examining the role of the U.S. Central Intelligence Agency during the Cold War won prestigious National Book Awards in New York City Wednesday.

Denis Johnson won the fiction award for his epic novel Tree of Smoke, the story of a CIA agent during the Vietnam War. The non-fiction prize went to Legacy of Ashes, Tim Weiner's history of the U.S. spy agency. Weiner, a reporter for the New York Times, won a Pulitzer Prize in 1988 for his reporting on secret national security programs.

Sherman Alexie won the young people's literature prize for The Absolutely True Diary of a Part-Time Indian, the story of a young Native American living on a poverty-stricken reservation. Robert Hass, a former U.S. poet laureate, won for his collection Time and Materials.

The winners each received a $10,000 prize.

Novelist-essayist Joan Didion received the 2007 Medal for Distinguished Contributions to American Letters. She used her acceptance speech to praise the late writer Norman Mailer, who received the award in 2005.

Mailer died last Saturday at the age of 84.

Among the noted writers who have received the prestigious award are John Updike, Philip Roth and Ralph Ellison.

Some information for this report was provided by AP and Reuters.