| Offenbach, Jacques, 1819-1880 | New version of Les contes d’Hoffmann (The tales of Hoffman) | PDF Book |
| Oldroyd, Osborn H. (Osborn Hamiline), 1842-1930 | The Good Old Songs We Used to Sing, ’61 to ’65 | PDF Book |
| Oliver, Stephen, 1950- | Unmanned | PDF Book |
| Orr, Charles Ebert, 1861-1933 | The Gospel Day; Or, the Light of Christianity | PDF Book |
| Ostaijen, Paul van, 1896-1928 | Bezette stad | PDF Book |
| Otis, James, 1848-1912 | The Boys of ’98 | PDF Book |
| Otto, Rudolf, 1869-1937 | Naturalism and Religion | PDF Book |