In the Unwalled City takes its title from Epicurus, who wrote: "Against other things it is possible to obtain security, but when it comes to death, we human beings all live in an unwalled city." This affecting book-which weaves prose memoir with poetry-explores that feeling of being open to attack-in this case the pain of grief after Robert Cording's thirty-one-year-old son Daniel died. To borrow a phrase from C.S. Lewis, here is...