Book excerpt: For many people the doctrine of the Trinity is a hopeless puzzle, an outdated philosophical idea far removed from everyday life. What does it all mean? And how can something so mysterious possibly make a difference in our everyday lives? In Experiencing the Trinity Darrell Johnson shows that this doctrine is not only at the heart of biblical Christianity, but that it is also at the center of Christian experience-of following Jesus Christ in ordinary life and seeing God at work in our human relationships. "At the center of the universe is a relationship," writes Johnson. "That is the most fundamental truth I know. It is out of that relationship that you and I were created and redeemed. And it is for that relationship that you and I were created and redeemed."