| The Opera / A Sketch of the Development of Opera. With full Descriptions of all Works in the Modern Repertory.
R. A. Streatfeild | |
| The Operatic Problem
William Johnson Galloway | |
| The Opinions of a Philosopher
Robert Grant | |
| The opinions of Jérôme Coignard
Anatole France | |
| The Opium Habit
Horace B. Day | |
| The Opium Monopoly
Ellen N. La Motte | |
| The Oppressed English
Ian Hay | |
| The optimist
E. M. Delafield | |
| The Optimist's Good Morning
Unknown | |
| The Orange Fairy Book
Andrew Lang |
