- Opening Doors
- Opening Doors: Roe v Wade
- Opening Mexico
- Opening NATO's Door
- Opening Schools and Closing Prisons
- Opening Skinner's Box
- Opening the American Mind: Recognizing the Threat to the Nation
- Opening the Books of Moses
- Opening the Doors
- Opening the Great Depths
- Opening the West with Lewis and Clark By Boat, Horse, and Foot up the Great River Missouri, Across t...
- Opening the West with Lewis and Clark. 1804, 1805, 1806
- Opening to Omnilateralism
- Openings & Outings
- Opera after 1900
- Opera After the Zero Hour
- Opera and the Political Imaginary in Old Regime France
- Opera in the Jazz Age
- Opera in the Tropics
- Opera inedita
- Opera Remade, 1700-1750
- Operace Dunaj
- Operace Dunaj aneb Internacionální vražda Pražského jara
- Operace Redwing
- Operace Stepní požár
- Operaciones especiales en la Edad de la Caballería
- Operaciones secretas: Las acciones más sucias del espionaje mundial
- Operación América Fidel Castro gestor del terrorismo comunista contra Latinoamérica
- Operación Anorí 1973 Derrota militar del Eln: Muerte de Antonio y Manuel Vásquez Castaño
- Operación Barbarroja: Una Guía Fascinante de los Primeros Meses de la Guerra entre Hitler y la Unión...
- Operación Exterminio
- Operación exterminio. 50 años de agresiones contra Cuba
- Operación Farinato
- Operación Forager
- Operación Fénix. Explosivas revelaciones de los computadores de Raúl Reyes
- Operación Mangosta
- Operación Marquetalia Mitos y Realidades del origen de las Farc
- Operación Odiseo 2011 Así cayó Alfonso Cano ideólogo del terrorismo de las Farc
- Operación siglo XX
- Operación Sodoma Muerte del Mono Jojoy: Caída del capo del narcotráfico y el terrorismo de las Farc
- Operación Turia
- Operaio in mare aperto
- Operate Your Rifle Like a Pro – U.S. Army Official Manual
- Operatic Geographies
- Operating Below Crush Depth
- Operation Agreement
- Operation Ajax: A Case Study on Analyst-Policy Maker Tensions and the Challenges of Estimative Intel...
- Operation Alacrity
- Operation Anaconda: An Air Power Perspective - Unique Case Study in Application of Force, Lessons on...
- Operation Anaconda: Lessons for Joint Operations - Analysis of Complex Afghanistan War Battle, Probl...
- Operation Anaconda: Lessons Learned, or Lessons Observed? Looking at Inconsistencies and Omission in...
- Operation Backhander
- Operation Bagration, 23 June-29 August 1944
- Operation Barbarossa: Nazi Germany's War in the East, 1941-1945
- Operation Big
- Operation Big Ben: The Anti-V2 Spitfire Missions
- Operation Broken Reed
- Operation Cakewalk
- Operation Certain Death
- Operation Chariot
- Operation Chowhound
- Operation Colossus
- Operation Compass
- Operation Corporate: Operational Artist's View of the Falkland Islands Conflict
- Operation Crossbow
- Operation Crossbow 1944
- Operation Crossroads - Lest We Forget! An Eyewitness Account, Bikini Atomic Bomb Tests 1946
- Operation Crusader and the Desert War in British History and Memory
- Operation Danube Reconsidered
- Operation Desert Storm
- Operation Dingo
- Operation Dragon
- Operation Dragoon
- Operation Dragoon: Unified Land Operations and Elements of Operational Art in Southern France - Vita...
- Operation Dynamo
- Operation Dynamo: The Battle of Dunkirk
- Operation Eagle Claw 1980
- Operation Enterprise: The Battle for Salisbury, Rhodesia
- Operation Family Secrets
- OPERATION FORAGER: Air Power in the Campaign for Saipan
- Operation Fortitude: The Closed Loop D-Day Deception Plan
- Operation Führerhauptquartier
- Operation Galvanic
- Operation Goodwood
- Operation Heartbreak
- The Way Home
- Operation HUSKY: A Critical Analysis
- Operation Husky: Operational Art in Large Formation Combined Arms Maneuver - Study of Allied Army Wo...
- Operation Iceberg
- Operation Idris
- Operation Iraqi Freedom
- Operation Ivy Bell
- Operation Jedburgh
- Operation Johannesburg
- Operation Jubilee
- Operation Just Cause: The Planning and Execution of Joint Operations in Panama - Noriega, Media and ...
- Operation KE
- Operation Kronstadt
- Operation Lena and Hitler's Plots to Blow Up Britain
- Operation Long Jump
- Operation Market Garden
- Operation Market Garden: Case Study for Analyzing Senior Leader Responsibilities
- Operation Market-Garden 1944 (2)
- Operation Market-Garden: Ultra Intelligence Ignored
- Operation Massacre
- Operation Matador
- Operation Medusa
- Operation Mekong
- Operation Millpond: U.S. Marines in Thailand, 1961 - Air America Covert Operations, Udorn Airfield, ...
- Operation Millpond: U.S. Marines in Thailand, 1961 [Illustrated Edition]
- Operation Mindstorm
- Operation Mongoose
- Operation Morthor
- Operation Neptune [Illustrated Edition]
- Operation Nightmare
- Operation Nimrod: The Iranian Embassy Siege
- Operation Overlord, Design and Reality; The Allied Invasion of Europe
- Operation Oyster World War II's Forgotten Raid
- Operation Peace for Galilee
- Operation Pedestal