Waves of Change: A Study of Social Mood by Mikko Ketovuori reveals a hidden force behind history, politics, culture, and markets known as collective mood. We are not only Homo sapiens rational thinkers but Homo sentiens feeling humans. Our shared emotions rise and fall in powerful cycles, shaping events long before they unfold. Revolutions, booms and busts, cultural shifts, and even artistic breakthroughs are not random; they follow the tides of social mood. Through thirteen essays, this book connects music, media, history, and economics and shows how optimism and fear, hope and despair, move societies and eras. Provocative and engaging, Waves of Change invites its readers to see the world differently and to recognize the unseen currents carrying us into the future. History doesn t repeat itself social mood does.