"The protagonist of Percival Everett's puckish new novel is a brilliant professor of mathematics who goes by Wala Kitu. (Wala, he explains, means "nothing" in Tagalog, and Kitu is Swahili for 'nothing.') He is an expert on nothing. That is to say, he is an expert, and his area of study is nothing, and he does nothing about it. This makes him the perfect partner for the aspiring villain John Sill, who wants to break into Fort Knox to steal, well, not...