This book provides an interdisciplinary theory that challenges traditional sociology by its superior ability to explain the irrational or unplanned aspects of culture, and it reveals that our society is not as rational as we would like to believe. The reader receives a comprehensive overview of cultural selection theory, including the history of the theory and the many different schools of thought, as well as an explanation of the nuts and bolts of cultural selection and the different selection mechanisms. Furthermore, the author introduces the new paradigm-breaking cultural r/k theory - a theory which reveals causal connections between religion, politics, ethics, art, and sexual behavior; and which can explain such diverse phenomena as the fall of Rome, the advent of rock music in the late Soviet Union, and the anti-pornography movement in contemporary USA. The attraction of this theory lies in its impressive explanatory power and its usefulness for making predictions. Unlike some elaborate mathematical treatises, this book maintains a down-to-earth theory with the main focus on the explanation of real world phenomena, including religion, politics, music, art, architecture, clothing fashion, sexual behavior, sport, and play. It thereby provides a solid foundation on which to base further research in many areas of human culture, including anthropology, archaeology, political and religious history, art, social psychology, sexology, peace research and futurology.