Knight, Damon (Editor)Turning Points: Essays on the Art of Science Fiction New York Harper & Row (1977). 0060124326 / 9780060124328 First Edition Very Good Very Good Cloth spine. xii, 303 pp. Jacket has a couple of tiny nicks, stain to fore-edges of last few pages. Contents clean and tight. Signed by Isaac Asimov on the front free endpaper. Contributors include: Robert A. Heinlein, Arthur C. Clarke, C. S. Lewis, John W. Campbell, Aldous Huxley, Brian W. Aldiss, Poul Anderson, James Blish, Theodore Sturgeon, and others.