The reader probably is not surprised when learning the identity of the children's rescuer in chapter 29 because there has been plenty of foreshadowing of the emergence of Boo Radley from his isolation inside his family home. It would be an artistic fault on the part of Harper Lee to give so much attention to Boo without ever bringing him out of hiding, and meanwhile the novel is coming closer and closer to the end. The reader knows that Boo has been watching the children for a long time. He has been leaving them little presents in the oak tree, and once he stitched up the pants that Jem had caught in the barbed wire and left them where Jem could easily find them when he ventured back. The reader feels that Boo is a gentle soul, even if the children have a superstitious dread of him. When they are attacked in the pitch darkness on their way back from church, the reader quickly guesses that it must have been Boo who rescued them when Bob Ewell attacked them with the apparent intent to kill. The author had been saving the introduction of Boo Radley until almost the last moment in order to achieve a satisfying, if not a surprising, ending for her story. Boo was just about the only person who would know his way around in the darkness so well. He had been wandering around at night for years. The reader has the additional satisfaction of knowing that Ewell has gotten his comeuppance.