Every single one of us matters in the process of transforming our future - but do we really believe that? What if we are underestimating our individual and collective capacity to change ourselves, our cultures, and our systems to create a thriving future for all? Through the lens of quantum social change, Karen O'Brien presents a radically different way of thinking about how we address climate change and wider social change. Inspired by ideas from quantum physics and quantum social science, her book challenges the mindsets of certainty and determinacy that lure us into believing that there is nothing that we can do about complex global problems like climate change. It offers new ways to think about our potential to shift the cultures and systems that perpetuate them. Quantum social change takes us beyond seeing ourselves as parts of systems, in a classical, mechanistic sense, and instead invites us to see ourselves as systems, from a relational, quantum perspective. This relational lens on social change recognizes that small changes can make a big difference and introduces new ways of scaling sustainability. It was written for everyone interested in how they each can contribute to social change for an equitable and thriving planet. If there is a single take-away message from this book, it is that you matter more than you think.