The Jigsaw Puzzle of the Mystery of Existence explores the connection between human evolution, intelligence and religious practice. As our brains have grown and our society has become more complex, our ways of thinking, learning and experiencing the world have also evolved. The book examines the Flynn effect — our rising IQ across generations — and its possible causes, from better nutrition to intellectual stimulation. Intelligence is not only shaped by modernity. Religious traditions have long promoted cognitive and health benefits through meditation, prayer, fasting, pilgrimages and intellectual discussion. This book takes a rational, scientific approach to spirituality and asks the question: what is truly beneficial about religious practice? How does it affect our intelligence and well-being?