This document is the Air Force's premier statement of warfighting principles and beliefs. It is the senior doctrine publication from which all other Air Force doctrine flows. Historically, airpower has been associated with its more familiar and visible aspects, such as air-to-air combat, strategic bombing, and long-range heavy airlift. However, airpower has many less visible but equally important missions across the range of military operations: providing close air support and tactical mobility to our ground forces; positioning and resupplying remote forces; obtaining and providing detailed and timely intelligence, surveillance and reconnaissance; providing humanitarian relief; projecting world-wide command and control; and training of coalition partners in the use of airpower, just to name a few. Also, while many parts of the Air Force are visibly engaged in overseas expeditionary operations, other aspects of the Air Force are quietly at work day-to-day, overwatching the homeland. These include nuclear forces on alert; ground- and space-based national warning systems; cyberspace forces monitoring the security of military networks; and fighters on call to defend sovereign airspace.