Richard Kirwan, a former Director of Ordnance Survey Ireland, takes the reader behind the scenes into the minds and work of the early map-makers with accounts of their inventions, adventures, endurance and heroism in pre-Famine Ireland. Their struggles and achievements are counterpointed by the successful efforts of the author and the OS staff to bring the mapping of Ireland up to date with the help of photographic and computer technology in the final decades of the twentieth century.

This is also the story of a boy, brought up in Waterford, who loved the lines and boundaries on maps and got to know his city and its surrounds, its physical characteristics and its people in the company of a loving father and grandfather. Although Richard Kirwan lost his father when still a young teenager he never lost his affection for the old maps and the people who created them - both map-makers like the first director of Ordnance Survey, the great Thomas Colby, whose achievements are felt throughout the book as a kind of inspiration, and the people of Ireland who gave the maps their place names, their boundaries and their memories.