A comprehensive thousand-year chronicle of naval history around the British Isles and of the vital importance of sea power in safeguarding a realm that provided an inviting target for marauders. Rodger (The Insatiable Earl, 1994) assistant keeper at London’s Public Record Office, notes that England, in the period from the seventh to the ninth centuries, was profoundly vulnerable to penetration from the sea; Vikings, Celts, Danes, Bretons, and others raided without hindrance. Rodger lucidly covers both the tentative British exploration of the sea and the long evolution of seagoing ships, ranging from Viking longboats to the large galleys and caravels of later centuries that combined economy, speed, and maneuverability. Ships were vital to trade, and thus to a nation’s growth. Rodger points out that the sea, once English ships began to patrol it, served as both a defensive barrier and as a highway for trade and exploration. It took a long time, however, for England to effectively make the sea its first line of defense. Many incursions occurred even after the Norman conquest in 1066. Henry V, the first monarch to understand the use of sea power as a primary weapon of war, built a fleet that struck at the heart of French power in Normandy in 1415, finding it more effective than launching an expensive, risky overland campaign. The defeat of the seemingly invincible Spanish Armada in 1588 under Elizabeth I raised Britain to the status of world power. Government-backed piracy against English rivals brought home much revenue, since the sea was regarded as being beyond laws, treaties, and truces. Rodger includes over 250 pages of illustrations, notes, maps, a chronology, exhaustive data on ships, a glossary, and a bibliography, creating a kind of pocket reference library about England and the sea in the time period covered. An outstanding reference work, and a considerable scholarly achievement, but not a work recommended for leisurely reading.