| The Oregon Question
Albert Gallatin | |
| The Oregon Territory, Its History and Discovery
Travers Twiss | |
| The Oregon Trail: Sketches of Prairie and Rocky-Mountain Life
Francis Parkman | |
| The Organisation of the Royal Naval Artillery Volunteers Explained
Earl Thomas Brassey Brassey | |
| The Organism as a Whole, from a Physicochemical Viewpoint
Jacques Loeb | |
| The Organization of the Congregation in the Early Lutheran Churches in America
B. M. Schmucker | |
| The Oriel Window
Mrs. Molesworth | |
| The Oriental Religions in Roman Paganism
Franz Cumont | |
| The Oriental Republic of Uruguay at the World's Columbian Exhibition, Chicago, 1893
Carlos María de Pena; Honore Roustan | |
| The Oriental Rug / A Monograph on Eastern Rugs and Carpets, Saddle-Bags, Mats & Pillows, with a Consideration of Kinds and Classes, Types, Borders, Figures, Dyes, Symbols, etc. Together with Some Practical Advice to Collectors.
William De Lancey Ellwanger |
