Swapping the nine-to-five grind for the freedom of the great outdoors, Jonny Muir set off on a 5,000-mile cycling and walking odyssey. His mission? To visit the summit of the United Kingdom's 92 countries - in 92 days. Never mind unexploded shells in Yorkshire, biting bugs in the Cairngorms of the gruelling task of climbing the equivalent of 14 Everests, The Heights of Madness is a celebration of our homeland's high places. If you've ever wondered what the highest point in Norfolk is, or why 500,000 people climb Snowdon every year, this is the book for you.