In this working paper, Wendy Russell and Stuart Lester of the UK's University of Gloucestershire discuss why play is fundamental to the health and well-being of children. They argue that both state signatories to the United Nations Convention on the Rights of the Child (Article 31 of which enshrines the right to play) and adults generally should take seriously the importance of providing suitable conditions for children to play. In the words of Gordon Burghardt, quoted in the working paper, "The problem of defining play and its role is one of the greatest challenges facing neuroscience, behavioural biology, psychology, education and the social sciences generally... only when we understand the nature of play will we be able to understand how to better shape the destinies of human societies in a mutually dependent world, the future of our species, and perhaps even the fate of the biosphere itself."