Some additions to the list:
Revolutionary in Ireland (AKA:)
Memoirs of a Revolutionary by Seán Mac Stíofáin (Autobiography of the first Chief of Staff of the Provisional IRA)
The Story of The Irish Race by Seumas Mac Manus (Self explanatory, ends around the time of the Treaty of '21 if I remember correctly)
Principles of Freedom by Terence Mac Swiney (This book is available for reading for free online, click
here)
The American Connection by Jack Holland (A book about the connection of Irish Republicans in the U.S. and Ireland primarily in the 60's-80's, a lot about gun running)
Dílseacht — the story of Comdt-General Tom Maguire and the Second All-Ireland Dáil by Ruairí Ó Brádaigh (An easy to read biography with loads of great information and history, plus fantastic pictures and scans)
Accepting The Challenge - The Memoirs of Michael Flannery edited by Dermot O' Reilly (The autobiography of an IRA volunteer who helped re-establish the Irish Republican Movement in the U.S.A. and made it more successful than ever before)
Republican Voices edited by Kevin Bean & Mark Hayes (Republicanism as told by Republican former Prisoners of War. Deals primarily with the 70's-90's)
Unmanageable Revolutionaries by Margaret Ward (A great introduction to the history of Female Republicans)