And he's also rumored to be the real writer of "To Kill a Mockingbird."
A great book on Capote, that covers that rivalry, (between Capote and Harper Lee) - is Capote, by Gerald Clarke. Unusually fine biography. I don't believe it rumor by the way. But Capote was very annoyed that his life-long friend made such a splash with Mockingbird, which became an instant American classic.
The character Dill, in To Kill A Mockingbird, is based on Capote, though.