It would seem at first blush to be hubristic to write yet another biography of Billy Graham, especially one that focuses on his relationships with American presidents. At 88, Graham is, and has been for more than five decades, one of the most celebrated men in history, the subject of dozens of biographies and one excellent autobiography. And the evangelist’s own transparent nature and predilection for truth telling make a portraitist’s job both too easy and too hard: he is exactly what he seems to be. For all these reasons, you might imagine that there’s nothing new to say about him.