William Timothy O'Brien (born October 1, 1946) is an American novelist. He is best known for his book The Things They Carried (1990), a collection of linked semi-autobiographical stories inspired by O'Brien's experiences in the Vietnam War. In 2010, The New York Times described O'Brien's book as a Vietnam classic. In addition, he is known for his war novel, Going After Cacciato (1978), also about wartime Vietnam, and later novels about postwar lives of veterans.