Before the political rupture between Russia and the West, resulting from Russia's annexation of Crimea in 2014 and subsequent invasion of Ukraine in February 2022, there was a complex programme of military cooperation between the Royal Navy and Russian Navy. Since 1988, the Royal Navy, first with the Soviet Navy and then the Russian Federation Navy, developed a close working relationship, signing a Memorandum of Understanding in 1998 on naval cooperation. The book examines this unique period of history and the lessons that were learned by both sides about how their respective navies operated, and the lessons drawn by Russia about the application of its maritime power in protecting its national interests globally. In light of the ongoing conflict in Ukraine and the deep divisions between the Euro Atlantic community and Russia, the maritime environment is an important arena in which the UK will be defending itself against Russia and its strengthening naval forces, while also deterring it, and through which military to military dialogue could be re-established. This fascinating period of naval cooperation provides lessons for all three elements of this defence engagement with Russia, especially looking forward into an uncertain future.