In medieval romance literature, a knight-errant is a traveller of noble birth in search of adventures in which to exhibit military skill, valour and generosity. Count Carl Gustaf von Rosen was all that, although he did not explicitly look for adventures. His forty-year flying career took him to different parts of the world, giving him a bird's-eye view of the unfair distribution of global wealth. He started as a Red Cross pilot in Ethiopia during the Italian war of 1935-1936, he built an Air Force for Emperor Haile Selassie from 1946 to 1956, and he experienced the painful birth of new...