Before the political rupture between Russia and the West--triggered by Russia's annexation of Crimea in 2014 and the invasion of Ukraine in 2022--the Royal Navy and the Russian Navy engaged in a complex programme of military cooperation. From 1988, the Royal Navy first collaborated with the Soviet Navy, then the Russian Federation Navy, culminating in a 1998 Memorandum of Understanding on naval cooperation. This book explores that unique period, examining how both navies operated and the lessons Russia drew about maritime power in advancing its global interests. With the ongoing conflict in Ukraine and growing tensions between Russia and the Euro-Atlantic community, the maritime domain remains a critical arena for defence, deterrence, and potential military dialogue. The lessons from this era of cooperation offer valuable insights for navigating an uncertain future.