A hilltop chimney in the foothills of the Dublin Mountains is a very prominent landmark, seen from land and sea. In the Glendalough valley and the adjacent Glendasan, ruined buildings and piles of spoil form very different landmarks. This volume explores the connection between the two, how they got there and when, looking at a very successful and profitable lead mining and smelting business occupied these sites in the nineteenth century. The book is the result of detailed research and investigations over nearly four decades and is illustrated by historic photographs, maps and engravings as well as more recent photographs to show the rich mining heritage at these separate, but related sites.