| Oxford poetry, 1921
Unknown | |
| Oxford Water-Colours
John Fulleylove | |
| Oxford: A Sketch-Book
Fred Richards | |
| Ox-Team Days on the Oregon Trail
Ezra Meeker; Howard R. Driggs | |
| Oxy-Acetylene Welding and Cutting / Electric, Forge and Thermit Welding together with related methods and materials used in metal working and the oxygen process for removal of carbon
Harold P. Manly | |
| Oxy-acetylene welding manual
Lorn Campbell | |
| Oysters and Fish
Thomas J. Murrey | |
| Ozma of Oz / A Record of Her Adventures with Dorothy Gale of Kansas, the Yellow Hen, the Scarecrow, the Tin Woodman, Tiktok, the Cowardly Lion, and the Hungry Tiger; Besides Other Good People too Numerous to Mention Faithfully Recorded Herein
L. Frank Baum | |
| Ozoplaning with the Wizard of Oz
Ruth Plumly Thompson | |
| Ozymandias
Ivar Jorgensen |
