Authors
- O
- Liam O Broin 1
- Finnian O Cionnaith 1
- Daibhi O Croinin
- Raghnall O Floinn
- Sean P. O Riordain
- O.E.C.D.
- O.I.C.
- Edgar O'Ballance
- George O'Bannon
- Sean O'Beirne
- T.H. O'Beirne
- A. Mor O'Brian
- Patrick O'Brian 6
- O'Brien
- A. Mor O'Brien
- Anita O'Brien
- Brendon O'Brien
- Charles O'Brien
- Charlotte O'Brien
- Conor O'Brien
- Conor Cruise O'Brien
- D.V. O'Brien
- Dan O'Brien
- David O'Brien
- Edna O'Brien
- F.T. O'Brien
- Flann O'Brien
- Frederick O'Brien
- J. O'Brien
- Jack O'Brien
- Jacqueline O'Brien
- James O'Brien
- John O'Brien
- Joseph F. O'Brien
- Kate O'Brien
- Lucy O'Brien
- Maire O'Brien
- Margaret L. O'Brien
- Martin O'Brien
- Mary Louise O'Brien
- Michael O'Brien
- P. O'Brien
- Pat O'Brien
- Patrick O'Brien
- Patrick K. O'Brien
- R.L. O'Brien
- Rick O'Brien
- Robert O'Brien
- Robert C. O'Brien
- T.P. O'Brien
- Terence O'Brien
- William O'Brien
- Conrad O'Brien-french
- Dermot O'Byrne
- Robert O'Byrne
- W. Lorcan O'Byrne
- William R. O'Byrne 1
- Karen O'Callaghan
- Sean O'Callaghan
- M.J. O'Carroll
- Eileen O'Casey 1
- Sean O'Casey
- Cyril O'Ceirin
- Kit O'Ceirin
- Helen O'Clery
- Carol O'Connell
- D.P. O'Connell
- Geoffrey O'Connell
- J.R. O'Connell
- John O'Connell
- John P. O'Connell
- Mary O'Connell
- Michael O'Connell
- Sheldon O'Connell
- O'Connor
- Anthony O'Connor
- Armel O'Connor
- Bernard O'Connor 1
- Betty O'Connor
- Carol A. O'Connor
- D. O'Connor
- D.J. O'Connor
- Dagmar O'Connor
- Daniel O'Connor
- David A. O'Connor
- Denis O'Connor
- E.A. O'Connor
- Flannery O'Connor
- Frank O'Connor 1
- Freddy O'Connor
- G. O'Connor
- G.F. O'Connor
- G.W. O'Connor
- Garry O'Connor
- Gillian O'Connor
- Gladys O'Connor
- J. O'Connor
- James O'Connor
- Jane O'Connor