In this book Ballantyne has brilliantly woven the story of a family that worked on the building of the Eddystone lighthouse, with the story of the actual building.   Three successive attempts were made to build a lighthouse on this dangerous rock which lies several miles off the south coast of Devon, and on which so many fine ships making their way up the English Channel to the North Sea ports of Europe had been wrecked.

The first attempt was made in the early years of the eighteenth century, but that lighthouse did not last long.  The second was made by Rudyerd, and was very well made and strong, but its upperworks were made of timber, and the whole thing was destroyed by fire, after having shown a light for over a third of a century.  There was an amusing episode during the construction of the Rudyerd lighthouse when a French warship took all the construction workers prisoner, and made off with them to France.  Luckily Louis, the King of France, heard of this and was quite incensed, ordering the British prisoners to be released and treated as hospitably as possible, while the captain of the warship was to be cast into the prison.

The final construction was by a mathematical instrument maker, of all people, called Smeaton.  His lighthouse was even more soundly founded than even Rudyerd’s had been, and he used the fact that stone is heavier than timber to add weight to the building, thus rendering it more resistant to the forces of wind and water.  It was not only succesful as a lighthouse, but it has lasted to this day, well over two centuries, and has ever since it was completed been a highly-regarded example of the art of lighthouse building.