Norman Mailer is at the top of his game in “On Sartre’s God Problem,” an essay that appeared in Libération, the liberal French daily, which recently marked the centenary of the French philosopher’s birth. Reprinted in the current issue of The Nation, it begins: “I would say that Sartre, despite his incontestable strengths of mind, talent and character, is still the man who derailed existentialism, sent it right off the track.” Then Mailer lays out his reasons in sweet detail and leads us to an even sweeter conclusion: “Something immense may now be stirring, but to meet it we will do better to expect that life will not provide the answers we need so much as it will offer the privilege of improving our questions.”