- O Comedor de Pregos e Outras Histórias
- Obama: An Intimate Portrait
- Oberst Hannes
- Occupational Hazards
- Ocean Devil
- Octavia, Daughter of God
- Odd Boy Out
- Odette
- Of Fortunes and War
- Official and Confidential: The Secret Life of J Edgar Hoover
- Oh ... Oberlin
- Old Man Goya
- Old World Hero Stories - Volume I - Ancient Hero Stories
- Olga's Story
- Oliver Cromwell (Penguin Monarchs)
- Olof Palme - Vor uns liegen wunderbare Tage
- Olympe de Gouges
- On Patriotism
- On Stalin's Team
- On Tyranny
- Once A Grand Duke
- Once upon a Secret
- One Bright Moon
- One Bullet Away
- One Dog at a Time
- One Hundred Days (Text Only)
- One Minute To Midnight
- One of the Family
- One of Us
- One Pair of Hands
- Open Secret
- Operation Jihadi Bride
- Operation Mayhem
- Operation Morthor
- Opowiadania kołymskie
- Oración fúnebre a las honras del rey nuestro señor don Felipe Cuarto el Grande
- Oriana Fallaci
- Orte der Erinnerung
- Oscar's Books
- Oskarżam Auschwitz
- Otto von Bismarck - Gedanken und Erinnerungen
- Our Boys
- Our Great Purpose
- Our Last Best Chance
- Our Man
- Our Revolution
- Our Story
- Our Young Soldier
- Out Of The Storm
- Out Of The Wilderness
- Outlandish Knight
- Outwitting the Hun
- Over There - War Scenes on the Western Front
- Overworld