Book excerpt: The questions of metaphysics are among the deepest and most puzzling. What is time? Am I free in my actions? What makes me the same person I was as a child? Why is there something rather than nothing? Riddles of Existence makes metaphysics genuinely accessible, even fun. Its lively, informal style brings the riddles to life and shows how stimulating they can be to think about. No philosophical background is required to enjoy this book: anyone wanting to think about life's most profound questions will find Riddles of Existence provocative and entertaining.