Nature-writing is going through a renaissance. What started largely with TV tie-ins has evolved into a genre encompassing books about climate change, the countryside, walking, and off-grid living. For Radio 4's new landmark environment and nature series, Rare Earth, presenters Tom Heap and Helen Czerski are joined on-stage at the Hay Festival by Mark Cocker, Philippa Forrester and Chris Thorogood to discuss the purpose of nature-writing, why it's important, and how nature-writing can help shape our understanding of the natural world. Produced by Emma Campbell for BBC Audio Wales and West in conjunction with the Open University