By Bella Bathurst

HarperCollins. 278 pp. $24

Reviewed by Ken Ringle

Even in this age of Global Positioning System (GPS) navigation and radar, there remains something enduringly and endearingly iconic about lighthouses. Their images adorn posters and paintings and greeting cards. Insurance companies use them in advertising. So powerful is their allure that the government spent millions last summer moving the erosion-threatened but obsolescent Cape Hatteras lighthouse out of harm's way. Who will ever get that sentimental about a radio beacon?

Now comes Bella Bathurst with a quirky little book that can only deepen the pharos fascination. Who remembers, if they ever knew, that Robert Louis Stevenson, author of Kidnapped and Treasure Island, sprang from a family who for three generations planted lighthouses on some of the world's most inaccessible and hazardous rocks? Her story of the Lighthouse Stevensons becomes inevitably the story of their astonishing engineering achievements on the forbidding, storm-ripped coast of Scotland, and, to some extent, of engineering's evolution from a trade to a profession.

In an era when Coast Guard helicopters routinely pluck mariners from hurricanes and the world sea paths are buoyed and beaconed for container ships on autopilot, it's easy to forget how recent the very concept of maritime safety is. Until the late 18th century, the public was more than content to consign sailors to the power of God and their captain. Yet so perilous was seafaring that one-third of all British seamen died pursuing their trade. In the 1790s an average of 550 ships were wrecked every year on British shores alone. By 1830 the total had climbed to nearly two a day. The northern coast of Scotland, where the North Sea collides with the Atlantic in a witches' brew of crosswinds, shoals and 10-knot riptides, was a particular graveyard. In 1799, 70 ships were lost in the Firth of Tay alone, a fraction of Scotland's 5,100 miles of coastline.

Yet when public agitation for government action finally took form, it met opposition from two curious quarters. The first were coastal "wreckers," who looked on shipwrecks and cargo that washed their way as a legitimate living from the sea. The second were churchly fundamentalists who looked on shipwrecks as a sort of divine judgment. Wouldn't a system of warning lighthouses amount to man attempting to thwart God's will?

Into these rocky political waters sailed Robert Stevenson, the author's grandfather, an industrious Edinburgh engineer who embraced the high-profile challenge of lighthouse building as a passport from the tradesman's world to middle-class respectability. His greatest monument was the Bell Rock lighthouse east of Dundee, marking a deadly sandstone reef that vanished under seven feet of water at high tides in a region where winter storms flung waves 70 feet high. It took five years to build, a massive 100-foot spire of granite blocks weighing as much as a ton apiece. The walls at the base are nine feet thick. It's still standing today.

Robert's son Alan did him one better. He built the 138-foot Skerryvore light, on a terribly exposed reef 12 miles from land northwest of Glasgow. It took seven years and 150 workmen to build, and it's been called the most beautiful lighthouse in the world.

The conditions under which workmen labored on such structures defy imagination, and at times one wishes Bathurst had spent a bit less time detailing the bureaucratic minutiae of Scotland's civil service and a bit more on the sheer physical drama of the construction. How, for example, did one even approach and land on such ship-killing reefs in sailing vessels, much less off-load thousands of tons of granite? How did one hoist the massive blocks in place with so little working room and so much required precision? The few tables and illustrations that Bathurst gives us just stoke the hunger for more.

Still, she paints remarkable pictures of terrified workmen huddling in storm-lashed barracks, expecting every moment to be swept away, and of storms that erased a season's work in a night. When Robert's grandson David was conducting surveys for the 1854 light at Muckle Flugga, a gale-whipped dot of stone off the northern tip of the Shetland Islands, Bathurst notes, "the seas in the area were so atrocious that it was commonplace during winter for unbroken waves to sweep right over the 200-foot summit of the rock. . . . He made note of a six-ton block of stone . . . torn from its moorings 80 above sea level and hurled into the sea below. This, he reported drily, `clearly proves that on these coasts we have elements to encounter of no ordinary nature.' "

The Lighthouse Stevensons is a work of no ordinary nature either, and we can only applaud Bathurst for giving us history as intriguing and illuminating as a Fresnel lens.

Ken Ringle is a writer, critic and mariner in The Post's Style Section.