Robert Louis Stevenson's grandfather, the foremost lighthouse engineer of his time, is the subject of a biography that is also a study of lighthouses, their construction, illumination and maintenance. Most of his work--including his masterwork, the Bell Rock sea tower--took shape on the remote reaches of Scotland, and the lore of the Hebrides, Orkneys and Shetlands intrigued his friend Walter Scott and his grandson Louis, both of whom joined his annual inspection cruise. (The northern lighthouses were, in fact, a family fixture, Robert succeeding his stepfather, his son Thomas succeeding him.) Much of this, however, concerns the technical development of lighthouses generally and Stevenson's contribution thereto, and to that extent it supplements the recent Carse history. It's a sober, responsible, not uninteresting account embodying the enthusiasm of the Stevensons for the subject--if anybody's looking.