Book excerpt: The Caledonides are a major orogenic belt that stretches from the Arctic, through Scandinavia, East Greenland, Britain and Ireland into the Atlantic coast of North America. Following the break-up of Rodinia, the Caledonides formed in the Palaeozoic by the drifting of various continents and their eventual aggregation in the Silurian and Devonian. The orogen subsequently fragmented during the opening of the Atlantic Ocean. This volume brings together 25 papers presenting the results of modern research that investigates the orogenic processes and the provenance of specific components of the belt. The contributions reflect different lines of research, linking traditional field studies with modern analytical techniques. In addition three overview papers summarize the main features of the belts in Scandinavia, Svalbard, East Greenland, Britain and Ireland, highlighting the advances made since the last major synthesis of the Scandinavian Caledonides 30 years ago, and discussing important open questions.