Two Hours is a kind of Hoop Dreams for runners. Ed Caesar follows a handful of Kenyan marathoners, tracks their races and careers, and talks to them about their lives. Part of what’s moving about the book is the sense you get that these athletes (the children mostly of subsistence farmers from the Rift Valley in East Africa, who sometimes had to break rocks to pay for their primary schooling) were born with an inheritance as rich as any Notting Hill trustfunder’s — except that instead of stock options and the deeds to a house they have inherited a series...