The wildly varied essays in Not-Knowing combine to form a posthumous manifesto of one of America’s masters of literary experiment. Here are Barthelme’s thoughts on writing (his own and others); his observations on art, architecture, film, and city life; interviews, including two previously unpublished; and meditations on everything from Superman III to the art of rendering Melancholy Baby on jazz banjolele. This is a rich and eclectic selection of work by the man Robert Coover has called one of the great citizens of contemporary world letters.