In announcing the award Monday, Publishers Weekly called the book "a serious critique of the two-party system, the corporations that finance it and the 'spineless cowards in the press' who 'aggressively print allegation and rumor independent of accuracy and fairness."'
Stewart, a comedian, is best known as the host of The Daily Show, a satirical news program that airs on the cable network Comedy Central.
His book was released in September and immediately topped best-seller lists even as Wal-Mart declined to stock the book, citing a page featuring the faces of the nine Supreme Court justices superimposed over naked bodies. The page facing the nude photos has cutouts of the justices' robes, complete with a caption asking readers to "restore their dignity by matching each justice with his or her respective robe."
Earlier this year Stewart sparked a feud that straddled the line between politics and entertainment when he appeared on the CNN debate show "Crossfire" and angered its bow-tied conservative host Tucker Carlson by calling the show "partisan hackery" that does little to advance the cause of democracy.