This book is longlisted for the 2014 Thwaites Wainwright Prize. What is the shape of Britain? The country's outline, looking a little like a wingless dragon, is instantly recognisable on any map or globe. But jostling within that familiar profile are countless vying maps of the country. Some of these are founded on rock - or on the natural features of the land. But far more are built on dreams - on human activity, effort, and aspiration. Britannia Obscura is an exploration of just a few of these surprising hidden Britains. Through a series of meetings with figures such as the retired army colonel and ley-hunter John Christian, the horse-boater Sue Day, and the cave-explorer Dave Nixon, each of the book's five chapters focuses on how a different group or community imagines the land and our relationship with it. On the megalith-hunter's map of Britain, the teeming metropolis of the country lies not in the South East, but rather amid the moors of its South West corner. The canal map of Britain reveals a land that takes four or five days to cross, and in which major transport routes lie forgotten beneath willowherb and litter. And on the ever-shifting and growing caver's map of Britain there are unknown regions still waiting to be discovered. Together, the book's chapters reveal that Britain is a country with countless competing centres and ceaselessly shifting borders - a land where one person's sleepy, remote and unexceptional province will always be the busy heart of another's map. The book also demonstrates that when viewed through the right lenses, Britain is a surprisingly large small island, which a lifetime of exploration could never exhaust. Ultimately, Britannia Obscura is a book that aims to make its readers more familiar with Britain but also excited about the endless possibilities for surprise that lie just around familiar corners.