One British response to the threat of Napoleon was to ring the English coasts with a series of heavily fortified observation towers. Over 200 of these towers were eventually built at enormous expense, not only on the British Isles, but in Australia, the West Indies and the Mediterranean.After the Napoleonic Wars some of the towers were demolished for building materials but many were dressed into service for storage and residence. While 43 towers survive in the British Isles, the most famous and the most frequently visited is the one outside Dublin at Sandycove. This was once the residence of James Joyce and is today a major James Joyce museum. For both the tourist and general reader, the author describes in detail both the history of these unique structures and all surviving examples in the British Isles and worldwide. For residents of the Western Hemisphere, the five towers built in Canada are described in detail with maps and photographs, as are the remains (most notably in Louisiana and Key West) of several American towers patterned after the British ones.