- Ontario Teachers' Manuals: Household Science in Rural SchoolsAuthor: Ontario. Department of EducationLanguage: English
- Ontario Teachers' Manuals: LiteratureAuthor: Ontario. Department of EducationLanguage: English
- Ontario Teachers' Manuals: Nature StudyAuthor: Ontario. Department of EducationLanguage: English
- OntboezemingenAuthor: Carel van NieveltLanguage: Dutch
- Oom Gert Vertel en Ander GedigteAuthor: C. Louis (Christiaan Louis) LeipoldtLanguage: Afrikaans
- Oomphel in the SkyAuthor: H. Beam PiperLanguage: English
- Oonomoo the HuronAuthor: Edward Sylvester EllisLanguage: English
- OorlogsvisioenenAuthor: Cyriel BuysseLanguage: Dutch
- Oowikapun, or, How the Gospel reached the Nelson River IndiansAuthor: Egerton Ryerson YoungLanguage: English
- Op de Faröer: De Aarde en haar Volken, 1907Author: Seé, AnnaLanguage: Dutch
- Op de jacht in Mozambique: De Aarde en haar Volken, 1909Author: Vasse, GuillaumeLanguage: Dutch
- Op de olifantenjacht in Oeganda: De Aarde en haar Volken, 1910Author: Langsdorff, Baron deLanguage: Dutch
- Op den Tarn: De Aarde en haar Volken, 1909Author: Mendell, M.Language: Dutch
- Op Eigen WiekenAuthor: Louisa May Alcott, G. W. (Gerardina Wilhelmina) Elberts, Daan de (Daniël) VriesLanguage: Dutch
- Op reis en thuis: Novellen en schetsenAuthor: Justus van MaurikLanguage: Dutch
- Op SamoaAuthor: E. von (Eginhard) BarfusLanguage: Dutch
- Open Source Democracy: How online communication is changing offline politicsAuthor: Douglas RushkoffLanguage: English
- Opening a Chestnut BurrAuthor: Edward Payson RoeLanguage: English
- Openings in the Old TrailAuthor: Bret HarteLanguage: English
- Opera Stories from WagnerAuthor: Florence AkinLanguage: English
- Operation HaystackAuthor: Frank Herbert, H. R. Van DongenLanguage: English
- Operation R.S.V.P.Author: H. Beam PiperLanguage: English
- Operation TerrorAuthor: Murray LeinsterLanguage: English
- Operation: Outer SpaceAuthor: Murray LeinsterLanguage: English
- Opere, Volume Secondo : scritti critici e letterariAuthor: Giovanni Berchet, Egidio BelloriniLanguage: Italian
- Opinions socialesAuthor: Anatole FranceLanguage: French
- Oppikirja suomalaisen kirjallisuuden historiassaAuthor: B. F. (Bernhard Fredrik) GodenhjelmLanguage: Finnish
- Opportunities in AviationAuthor: Arthur Sweetser, Lamont, GordonLanguage: English
- Opportunities in EngineeringAuthor: Charles M. (Charles Marcus) HortonLanguage: English
- OptionsAuthor: O. HenryLanguage: English
- Opuscula Selecta Neerlandicorum: Nederlandsch Tijdschrift voor GeneeskundeAuthor: Hector Treub, Herman Boerhaave, F. C. (Franciscus Cornelis) Donders, Desiderius Erasmus, Gaubius, Hieronymus DavidLanguage: Latin
- OpusculesAuthor: Jean-B.-A. (Jean-Baptiste-Antoine) FerlandLanguage: French
- Opúsculos por Alexandre Herculano - Tomo 01Author: Alexandre HerculanoLanguage: Portuguese
- Opúsculos por Alexandre Herculano - Tomo 02Author: Alexandre HerculanoLanguage: Portuguese
- Opúsculos por Alexandre Herculano - Tomo 04Author: Alexandre HerculanoLanguage: Portuguese
- Opúsculos por Alexandre Herculano - Tomo 05Author: Alexandre HerculanoLanguage: Portuguese
- Opúsculos por Alexandre Herculano - Tomo 07Author: Alexandre HerculanoLanguage: Portuguese
- Opúsculos por Alexandre Herculano - Tomo 08Author: Alexandre HerculanoLanguage: Portuguese
- Opúsculos por Alexandre Herculano - Tomo 09Author: Alexandre HerculanoLanguage: Portuguese
- Orange and Green: A Tale of the Boyne and LimerickAuthor: G. A. (George Alfred) HentyLanguage: English
- Oration on the Life and Character of Henry Winter DavisAuthor: John A. J. (John Angel James) CreswellLanguage: English
- Oração funebre recitada nas exequias do Illm.^o e Exm.^o Sr. Pedro Alexandrino da CunhaAuthor: António Augusto Teixeira de VasconcelosLanguage: Portuguese
- Orchesography, or, the Art of Dancing: The Art of Dancing by Characters and Demonstrative FiguresAuthor: Feuillet, Raoul-Auger, John WeaverLanguage: English
- Ordnance Instructions for the United States Navy.: 1866. Fourth edition.Author: United States. Navy Department. Bureau of OrdnanceLanguage: English
- Oregon, Washington and Alaska; Sights and Scenes for the TouristAuthor: E. L. (Edward Lloyd) LomaxLanguage: English
- Organic Gardener's CompostingAuthor: Steve SolomonLanguage: English
- Organic Syntheses: An Annual Publication of Satisfactory Methods for the Preparation of Organic ChemicalsAuthor: James Bryant ConantLanguage: English
- Oriental Encounters: Palestine and Syria, 1894-6Author: Marmaduke William PickthallLanguage: English
- Oriental Religions and Christianity: A Course of Lectures Delivered on the Ely Foundation Before the: Students of Union Theological Seminary, New York, 1891Author: Frank F. (Frank Field) EllinwoodLanguage: English
- Origin and Development of Form and Ornament in Ceramic Art.: Fourth Annual Report of the Bureau of Ethnology to the Secretary of the Smithsonian Institution, 1882-1883, Government Printing Office, Washington, 1886, pages 437-466.Author: William Henry HolmesLanguage: English
- Origin of the Anglo-Boer War Revealed: The Conspiracy of the 19th Century Unmasked: (2nd ed.)Author: Thomas, C. H.Language: English
- Original letters and biographic epitomesAuthor: J. Atwood (John Atwood) SlaterLanguage: English
- Original Short Stories — Volume 01Author: Guy de Maupassant, Henderson, A. E. [Translator], McMaster, Albert Cohn [Translator], Quesada, Louise Charlotte GarstinLanguage: English
- Original Short Stories — Volume 02Author: Guy de Maupassant, Henderson, A. E. [Translator], McMaster, Albert Cohn [Translator], Quesada, Louise Charlotte GarstinLanguage: English
- Original Short Stories — Volume 03Author: Guy de Maupassant, Henderson, A. E. [Translator], McMaster, Albert Cohn [Translator], Quesada, Louise Charlotte GarstinLanguage: English
- Original Short Stories — Volume 04Author: Guy de Maupassant, Henderson, A. E. [Translator], McMaster, Albert Cohn [Translator], Quesada, Louise Charlotte GarstinLanguage: English
- Original Short Stories — Volume 05Author: Guy de Maupassant, Henderson, A. E. [Translator], McMaster, Albert Cohn [Translator], Quesada, Louise Charlotte GarstinLanguage: English
- Original Short Stories — Volume 06Author: Guy de Maupassant, Henderson, A. E. [Translator], McMaster, Albert Cohn [Translator], Quesada, Louise Charlotte GarstinLanguage: English
- Original Short Stories — Volume 07Author: Guy de Maupassant, Henderson, A. E. [Translator], McMaster, Albert Cohn [Translator], Quesada, Louise Charlotte GarstinLanguage: English
- Original Short Stories — Volume 08Author: Guy de Maupassant, Henderson, A. E. [Translator], McMaster, Albert Cohn [Translator], Quesada, Louise Charlotte GarstinLanguage: English