The 19th century was a crucial period in naval history when great technological advances were made in almost every area of maritime military activity. This illustrated account of the period follows a summary of technology, tactics and strategy with accounts of warfare in the Napoleonic era and the factors that led to British naval supremacy. With the background to change now established, he proceeds to describe the revolutions that followed in naval ordnance, propulsion, iron hulls and underwater warfare, and how these were used in practice mid-century in the Crimean and American Civil Wars. He reviews the naval situation before World War I, examining naval thought and international attitudes towards battleship size, and speed versus armour, and shows how these important changes were put into practice in the Sino-Japanese, Russo-Japanese and Spanish-American wars. He concludes with an overview of the world naval balance on the eve of World War I.