The first recorded engagement by a steam-powered warship took place on a river, when in 1824 the Honourable East India Company's gunboat Diana went into action on the Irrawaddy in Burma. In the 150 years that followed river gunboats played a significant part in over forty campaigns and individual actions, down to the Portuguese and American 'Brown Water' fighting in Africa and Vietnam respectively at the end of the twentieth century. They proved to be the decisive factor in operations against the Maoris, with Gordon's Ever Victorious Army in China, during the river campaigns of the American Civil War, in the French conquest of Indochina, during Kitchener's advance on Khartoum, and on the Rufiji and Tigris during the Great War. River gunboats fought for the Paris Commune, on the rivers of South America, against the Bolsheviks, and during the Second World War in the open waters of the Mediterranean, while armored Soviet gunboats fought German Panzers, and a pair of 'Girls' attacked the Japanese on the banks of the Irrawaddy. This lavishly illustrated encyclopedia describes vessels of every nation designed as river gunboats, plus those converted river steamers which took part in combat. Maps of the river systems where they operated are included, together with narratives of the principal actions involving river gunboats. Their story is brought up-to-date with data on current riverine combat vessels in service today.