The Baltic Cauldron commemorates several centuries of Anglo-Swedish relations, which, after events in Eastern Europe in 2022, have acquired a new resonance as a record of the struggle for survival and independence of nations bordering the Baltic. This is a history of navies in the Baltic Sea and its approaches, from the Skaggerak to the Gulfs of Bothnia and Finland. This book portrays the relationship between the Swedish and British Navies over the centuries. In the 1700s Britain was a global naval power and developed doctrine, ships and culture which were copied by others, but the relationship with Sweden became special. While Britain and its navy depended upon Baltic Sea trade for timber, tar, iron and grain, the foundation was laid for the Swedish Navy, its self-image, tactics, materials and traditions. Among the subjects addressed are: the origins of the Swedish navy; the first English fleet to visit the Baltic; Charles XIIs amphibious campaigns; the English influence on Swedish shipbuilding; the quixotic Admiral Sir Sidney Smith; Admirals Lord Nelson and James Saumarez at war and peace; and, in the 20th century, the hunt for the Bismarck, Churchills planned attack on arctic Lulea in 1940, and blockade-runners in the Second World War. This ground-breaking study is filled with new insights, and contains much previously unpublished information, some based on Swedish sources which are not often quoted in the English-speaking world. The book is brought up to date with an account of the capture by Iranian forces of Stena Impero. Lessons in sea power are drawn throughout the book. The Baltic Cauldron is a fitting and worthy tribute to both the Royal Navy and to the Royal Swedish Navy at its quincentenary.