Keller's book is the work of an exceptional, thoughtful preacher. It is a remarkable publication, not coincidentally named Book of the Year 2008 by World Magazine, which later climbed to seventh place on the New York Times non-fiction bestseller list, and the author even became a best-selling author for a time). Critics called Keller "C. S. Lewis for the 21st century" not by chance: the well-known British writer and defender of the Christian faith C. S. Lewis became one of Keller's role models.

Timothy Keller uses a wealth of literary material from the fields of classic fiction, philosophy, Christian apologetics, theology, evolutionary biology, and a host of other fields to answer many of the questions asked by people seeking God. He systematically analyzes the questions, does not leave any out, and is not afraid of even the most delicate topics. Why is there suffering in the world? How can a loving God send people to hell? Why isn't Christianity more accessible to everyone? Is there only one true religion? Does the Bible have to be taken literally? Shouldn't the Christian God be a god of love? Does it even make sense to believe in anything? Has science disproved the validity of the Christian faith? Why were so many wars fought in the name of God?