- Oberheim (Voices): A Chronicle of WarAuthor: Leadem, ChristopherLanguage: English
- OddAuthor: Amy Le FeuvreLanguage: English
- Oeuvres de André Lemoyne: Une Idylle normande.—Le Moulin des Prés.—Alise d'Évran.Author: André LemoyneLanguage: French
- Oeuvres illustrées de George Sand: Les visions de la nuit dans les campagnes - La vallée noire - Une visite aux catacombesAuthor: George SandLanguage: French
- Of Human BondageAuthor: W. Somerset (William Somerset) MaughamLanguage: English
- Off on a Comet! a Journey through Planetary SpaceAuthor: Jules VerneLanguage: English
- Off to the Wilds: Being the Adventures of Two BrothersAuthor: George Manville Fenn, Henri Théophile Hildibrand, Edouard RiouLanguage: English
- Officer and Man: 1901Author: Louis BeckeLanguage: English
- Oh, Money! Money! A NovelAuthor: Eleanor H. (Eleanor Hodgman) PorterLanguage: English
- Oh, You Tex!Author: William MacLeod RaineLanguage: English
- Ohne den Vater: Erzählung aus dem KriegeAuthor: Agnes SapperLanguage: German
- Ojamylläri ja hänen miniänsäAuthor: Lydia Koidula, Forsman, Betty [Translator]Language: Finnish
- Okewood of the Secret ServiceAuthor: Valentine WilliamsLanguage: English
- Old Caravan DaysAuthor: Mary Hartwell CatherwoodLanguage: English
- Old ChristmasAuthor: Washington IrvingLanguage: English
- Old EbenezerAuthor: Opie Percival ReadLanguage: English
- Old Gold: The Cruise of the "Jason" BrigAuthor: George Manville Fenn, Stanley L. WoodLanguage: English
- Old Granny FoxAuthor: Thornton W. (Thornton Waldo) BurgessLanguage: English
- Old Jabe's Marital Experiments: 1908Author: Thomas Nelson PageLanguage: English
- Old JackAuthor: William Henry Giles KingstonLanguage: English
- Old KaskaskiaAuthor: Mary Hartwell CatherwoodLanguage: English
- Old Lady Mary: A Story of the Seen and the UnseenAuthor: Mrs. (Margaret) OliphantLanguage: English
- Old Lady Number 31Author: Louise ForsslundLanguage: English
- Old Rose and SilverAuthor: Myrtle ReedLanguage: English
- Old Saint Paul's: A Tale of the Plague and the FireAuthor: William Harrison AinsworthLanguage: English
- Old valentinesAuthor: Munson Aldrich Havens, Griswold TyngLanguage: English
- Ole Mammy's TormentAuthor: Annie F. (Annie Fellows) Johnston, Mary G. Johnston, Amy M. (Amy Maria) SackerLanguage: English
- Olive: A NovelAuthor: Dinah Maria Mulock Craik, G. (Georgina) BowersLanguage: English
- Oliver TwistAuthor: Charles DickensLanguage: English
- Oliver TwistAuthor: Charles DickensLanguage: French
- Olivia in IndiaAuthor: O. DouglasLanguage: English
- Olivia oder Die unsichtbare LampeAuthor: Jakob WassermannLanguage: German
- Olympian NightsAuthor: John Kendrick BangsLanguage: English
- Omatunto: SaaristokertomusAuthor: Juhani AhoLanguage: Finnish
- Omoo: Adventures in the South SeasAuthor: Herman MelvilleLanguage: English
- On a Torn-Away World; Or, the Captives of the Great EarthquakeAuthor: Rockwood, RoyLanguage: English
- On Board the Esmeralda: Martin Leigh's Log - A Sea StoryAuthor: Hutcheson, John C. (John Conroy), William Heysham OverendLanguage: English
- On Christmas Day In The EveningAuthor: Grace S. (Grace Smith) Richmond, C. M. (Charles M.) RelyeaLanguage: English
- On Our SelectionAuthor: Steele RuddLanguage: English
- On the Banks of the AmazonAuthor: William Henry Giles Kingston, William H. C. GroomeLanguage: English
- On the Church StepsAuthor: Sarah C. HallowellLanguage: English
- On the Edge of the Arctic; Or, An Aeroplane in SnowlandAuthor: H. L. (Harry Lincoln) Sayler, Hall, N. P. [Illustrator]Language: English
- On the eve: A novelAuthor: Ivan Sergeevich Turgenev, Constance GarnettLanguage: English
- On the Firing LineAuthor: Anna Chapin Ray, Fuller, Hamilton BrockLanguage: English
- On the StairsAuthor: Henry Blake FullerLanguage: English
- On With TorchyAuthor: Sewell Ford, Lincoln, F. Foster (Frederic Foster) [Illustrator]Language: English
- Once Aboard the Lugger-- The History of George and his MaryAuthor: A. S. M. (Arthur Stuart-Menteth) HutchinsonLanguage: English
- Once Upon A TimeAuthor: Richard Harding DavisLanguage: English
- Onder den rook der mijn: Eene novelle uit LimburgAuthor: Felix RuttenLanguage: Dutch
- Onder Moeders VleugelsAuthor: Louisa May Alcott, G. W. (Gerardina Wilhelmina) ElbertsLanguage: Dutch
- One Day: A sequel to 'Three Weeks'Author: Elinor GlynLanguage: English
- One Day At ArleAuthor: Frances Hodgson BurnettLanguage: English
- One Day's Courtship, and The Heralds of FameAuthor: Robert BarrLanguage: English
- One Man in His TimeAuthor: Ellen Anderson Gholson GlasgowLanguage: English
- One Man's Initiation—1917Author: John Dos PassosLanguage: English
- One of Life's SlavesAuthor: Jonas Lie, Muir, Jessie [Translator]Language: English
- One of Our Conquerors — CompleteAuthor: George MeredithLanguage: English
- One of Our Conquerors — Volume 1Author: George MeredithLanguage: English
- One of Our Conquerors — Volume 2Author: George MeredithLanguage: English
- One of Our Conquerors — Volume 3Author: George MeredithLanguage: English