Simply put, When the Light Goes Out documents Irish lighthouse fatalities from 1786 to 1972. But it is much more than this. In recording these tragic events in chronological order, the book builds into a history of lightkeeping in Ireland from the early years until almost the present day, recording the mostly forgotten stories of people in the service of Irish Lights, and the Ballast Board before it. As such it is a roll-call of honour of those who died while keeping our shores safe for the mariner and the fisherman. It also features many lighthouses that are now defunct or no longer exist, with many illustrations both ancient and modern.