The remote mountain loch of Lochnagar is one of the most studied freshwater bodies in Europe. It is an area of outstanding, although harsh, natural beauty, a favourite destination for hill-walkers and a rare UK habitat for many alpine species. This book brings together knowledge gained over two decades of multi-disciplinary scientific study, with the results of lake sediment research covering millennia, to show how the loch has developed both naturally and as a result of human impact. Particular emphasis is placed on how this fragile ecosystem, and others like it, which may be affected by future climate change.