In the parable that begins this book, a large chunk has fallen out of the roof of a historic church, exactly where an imposing mosaic of God enthroned in heaven used to reside. The members of the church, unable to agree on how to repair the roof or what image to put there, now worship under a God-shaped hole, trying to come to grips with the loss of old certitudes and the new challenges they face. The church today faces exactly the same problem, argues...