Lighthouses have always unsettled and attracted in equal measure, highlighting the triumphs and failures in humanity's battle with the forces of nature. Taking as its heroes the lighthouses themselves, Sentinels of the Sea describes the engineering genius that allowed their construction on even the smallest of rock outcrops and the innovations that made the lights so powerful and reliable. Intricate, elegant architectural plans and elevations, and evocative period drawings and photographs showcase the innovative designs and technologies behind fifty historic lighthouses built around the world from the 17th to the 20th century. R.G. Grant's engaging and authoritative text chronicles the incredible feats of engineering and endurance that brought these iconic, isolated towers into being, the advances in lens technology that made the lights so effective, and the everyday routines of the lighthouse keepers and the heroic rescues that some performed. Packed with extraordinary stories of human endeavour, desperate shipwrecks, builders defying the elements and heroic sea rescues, the book also reveals the isolation and vulnerability of the dedicated lighthouse keepers.