One of the coolest things about literature awards is that they introduce avid readers to writers they might never have heard of otherwise. The National Book Award is especially adept at this—partly because they seem more concerned with evaluating high quality literature and less concerned with remaining politically correct than some of their prize-giving counterparts, and partly because the authors they choose to recognize aren't celebrity-types.
That's not to say there are no well-known writers on the shortlist of National Book Award for Fiction. Au contraire, there are plenty: J.D. Salinger, John Steinbeck, Vladimir Nabokov, Toni Morrison, etc. But there are just as many less famous but eminently capable authors in the ranks: Kent Haruf, Louise Erdrich, Peter Matthiessen, Paul Theroux, Joshua Ferris.
Each year, a small army of writing professionals read hundreds of texts submitted by publishers to discover the best of American novels. Only one book by one author wins each year, but there are medalists whose work was shortlisted for the grand prize. The National Book Award is similar to the Man Booker Prize in the U.K., though it's been around for about a decade longer.
For whatever reason, the National Book Award seems far less concerned with pleasing the powers-that-be than comparable literary awards associations like the Pulitzer Prize or the Nobel Prize in Literature. Some winners of the National Book Award have been vocal Christians (Flannery O'Connor and Walker Percy come immediately to mind), and many others have evidenced a more moderate political stance than the typically Leftist attitudes of so many among the modern literati.
These aren't safe books, however, nor is there any lack of a liberal non-Christian worldview present in the works selected. Just because there are also a few conservative writers on the list doesn't mean the judges haven't balanced their presence with some crazy radicals like John Irving and Thomas Pynchon and Norman Mailer. But there are also some of the greatest writers of our era on the list (like Tim O'Brien and Cormac McCarthy), and just because a few bad apples got in doesn't mean they're all spoiled.
In many ways the National Book Award is the most intriguing of the literary awards, especially in the United States. It's judges are either extremely even-handed and diverse, or simply capricious. They're also seem far less restricted by common snobbery, and have even shortlisted a sci-fi writer (Oregon's own Ursula K. LeGuin). At any rate, there are some great writers and some bad writers who've won this prize, and THAT is the sign of a well-balanced panel of judges, and of a literary prize worth paying attention to.