The Smithsonian National Air and Space Museum in the US holds the country's premier collection of historic aircrafts. Each entry includes archival images of the craft and authoritative text that places each one in the context of the development of aviation technology and world history. Now retired after 30 years with the US Air Force Still Photo Depository and the National Air and Space Museum Archives, Dana Bell is a full-time aviation historian and author. He has written more than 20 books on aviation subjects. Eric F. Long is a senior photographer for the National Air and Space Museum. Mark A. Avino is the chief photographer for the museum.