William H. Gass has been sitting on The Tunnel for quite a while, and I do mean sitting. The author of a previous novel, a dozen or so stories, and several collections of essays, Gass began writing this book in 1966 … 1966—the year the Beatles recorded Revolver, Michelangelo Antonioni released Blow-Up, and Twiggy was fashion’s favorite Q-Tip. It was the year Susan Sontag became the sultry star of deep thought with Against Interpretation. It was six presidents ago, not counting Clinton. Now the psychedelic skies are gray. The bandannas are all undone. The Tunnel reflects the loosy-goosy period in which it was begun and the overriding sense of mission needed to span nearly thirty years of hard mental labor. It isn’t so much a novel as a Sisyphean labor, the uphill climb of a downhill life.

The narrator of The Tunnel is William Frederick Kohler, a historian and...