Over the past three decades, research and intervention processes have been left wanting by the lack of the substantive inclusion of children and young people, as well as the challenge of adultism - the ongoing and systematic disregard of many children and youth in decision-making. This book is inspired by the dedication of people across global contexts who have worked with children in communities to improve their lives, many of whom started out as youth activists. The inspirational authors of the chapters, many more who also work across global contexts with children in communities, and the editors own varied journeys in academia and activism have formed the basis of this book. All involved have tried to express a vision where conditions are improved to attain child and youth rights and intergenerational justice. In each chapter, practitioners and academics from many global contexts share their experiences of being youth activists and working with children and young people in a participatory way, broadly based on rights-based approaches emerging from the UN Convention on the Rights of the Child (UNCRC). A collection of interviews with field experts carried out as part of Rejuvenate, a partnership programme co-led by the Institute for Development Studies and the University of the Highlands and Islands, form the basis of the chapters of this book. Its chapters will inspire and support those working or seeking to work with children and young people in communities, from academic, local, national and international policy and practice, across different country and institutional perspectives.