Every Dark Hour is the first full-length history of Kilmainham Jail, one of Ireland's most visited tourist sites. Written by long-serving archivist, Niamh O'Sullivan, whose extensive knowledge of the jail and those who were imprisoned there composes a remarkable collage of human experience, the book is lavishly illustrated with many previously unpublished photographs.

Kilmainham Jail is perhaps the most important building in modern Irish history. A place of incarceration since its construction in the late eighteenth century, it housed a succession of petty criminals (including sheep rustlers) and, during the Famine, people who committed crimes with the sole aim of being imprisoned there: even the meager rations offered at the jail were better than what was available in other parts of the country.

It was a powerful symbol of British rule on the island of Ireland, its residents over the years included the bold Robert Emmet, Charles Parnell, and of course, it was also the place where the 1916 rebels were executed. Every Dark Hour is a colourful and entertaining telling of the history of the jail, a very human story rich with Irish heritage, populated by an endlessly colourful cast of characters in which O'Sullivan brings her comprehensive knowledge of all the sources relating to the building, from the official records to the graffiti on the walls, and her own personal impressions to bear. Every Dark Hour also chronicles the heroic men and women who gave freely of their time and energies to restore the jail to its former grandeur when it was on the verge of being reclaimed by the elements.