The Chamonix Valley and Mont Blanc massif is the global capital of trail running, home to the Ultra-Trail du Mont Blanc and some of the most dramatic mountain terrain in the Alps. Crossing three countries France, Switzerland and Italy with glaciers, high cols, technical ridgelines and sweeping alpine trails at every turn, it offers trail runners of every level an extraordinary concentration of world-class routes. With 40 routes ranging from a 3.8km introduction run to the full 168km UTMB circuit, this Cicerone guidebook by Kingsley Jones covers the full breadth of trail running across the Mont Blanc massif, graded by terrain type from wide trails to technical skyrunning. From short day runs above Chamonix to multi-country race recces, there is something for every runner. The 40 routes range from 3.8km to 168km and are graded 1 to 5, categorised as trail running, fell running or skyrunning, with information on distance, ascent, descent and timings for each Starting points include Chamonix, Les Houches, Servoz, Vallorcine, Champex, Courmayeur and Orsires, covering the full extent of the Mont Blanc massif across France, Switzerland and Italy Four international race recces are included: the full UTMB (168km), the OCC (Orsires, Champex, Chamonix), the CCC (Courmayeur, Champex, Chamonix) and the TDS (Traces des Ducs de Savoie) Step-by-step route descriptions are accompanied by 1:100,000 mapping and route profiles, with GPX files available to download for all 40 routes A comprehensive introduction covers running at altitude, adapting to the Alps, mountain skills, navigation, trail kit and mountain safety, alongside practical information on bases, travel and weather From your first alpine trail run to a full UTMB recce, this is the essential guide to running in one of the world's great mountain playgrounds.