A few months after finishing his short-story collection “CivilWarLand in Bad Decline,” George Saunders picked up Leo Tolstoy’s final work, “Hadji Murad,” for the first time.

“I was diving back into the Russians just trying to replenish the well a little bit,” says Mr. Saunders, winner of a MacArthur “genius grant” and this month’s WSJ Book Club host. “Somebody described this to me as a shrink-wrap version of ‘War and Peace’—the book in which Tolstoy had taken all the things he had learned as a novelist and kind of shrunk them...