His wife on the book he didn’t finish. 

 “I think he didn’t want to do the old tricks people expected of him,” Karen Green, his wife, says. “But he had no idea what the new tricks would be.” The problem went beyond technique. The central issue for Wallace remained, as he told McCaffery, how to give “CPR to those elements of what’s human and magical that still live and glow despite the times’ darkness.” He added, “Really good fiction could have as dark a worldview as it wished, but it’d find a way both to depict this world and to illuminate the possibilities for being alive and human in it.”

From the New Yorker. The whole thing is worth a read.