Play is fundamental to children's health, wellbeing and development. Yet in the modern world, their space and opportunity to play is under threat. This is the first book to look in detail at children's play within public policy. Using the UK government's play strategy for England (2008-10) as a detailed case study, it explores states' obligations to children under the UN Convention on the Rights of the Child and the General Comment of 2013. It presents evidence that strategies for public health, education and even environmental sustainability would be more effective with a better-informed perspective about the nature of play and the importance of allowing children more time and space for it. The book throws down a challenge to both play advocates and governments, to make effective policy that respects, protects and fulfils children's right to play as a priority. It is an essential tool for practitioners and campaigners around the world.