This book explores the environmental history of the British military through a comparative framework of five key sites in England and Wales. The military presence at these places, it is claimed, has protected them from more damaging land uses such as intensive agriculture, urban sprawl and industrial development. The book examines such claims and explores how and why the military has embraced nature conservation policies. The greening of the MOD and khaki conservation are critically examined in an historical context. The emergence of the training landscapes as protected spaces is contrasted with calls for greater access, and at times, public pressure for their release. The volume draws to attention the environmental impact of preparations for war, and brings sites of training to the fore alongside better known military landscapes like battlefields and conflict zones. Each chapter is based in a single site, giving prominence to local meanings and landscape character but allowing the overarching themes to connect throughout, tracing an environmental history of the UK Defence Estates that is firmly grounded in the British countryside.