Not believing in God is, on the one hand, a very simple matter. As most Danes and Swedes know, it is increasingly possible to grow up in a wholly secular environment, where questions about sin, grace, and an afterlife never get posed, where well-being is taken for granted, where people feel protected and reassured not by churches but by societal institutions. But on the other hand, as Sartre said, “becoming an atheist is a long a difficult undertaking.” Becoming an atheist in a religious culture entails sorting through a series of profound issues. To think through what this means and how to live one’s entire life in a world without God requires addressing, as Sartre knew, life’s ultimate questions about “man and the universe.” It is, in short, one thing to live as if God does not exist, but quite another to provide secular answers to Kant’s three great philosophical questions: “What can I know?”, “What may I hope?”, “What should I do?” This is what my book, Living without God, sets out to do.