Altitude medicine is fundamentally simple: if you don't feel well at high altitude, you shouldn't ascend further. However, whether trekkers or mountaineers, more and more people are seeking solitude in nature or aiming for great heights! Unfortunately, many fail due to a lack of knowledge about altitude issues. This medical guide aims to equip readers to optimally prepare for a planned trip. A number of contributors, all of whom are climbers, mountain guides, or doctors, have contributed to this work. In addition to chapters on trekking, acclimatization, and extreme altitude, topics such as training and polar medicine are also covered in detail. Valuable tips, illustrations, and equipment lists leave little room for questions at the end.