What is an example of symbolism in the novel, The Whisper Man?

The book The Power of Three is a symbol of connection. Pete feels this connection both to his son and his grandson when he reads this book to Jake. Pete remembers reading the same book to Tom when he was a child. He looks at the battered copy of the book from which Tom had been reading to Jake and wonders if that is the same book from which he once read to Tom.