The main part of the book centers on the discussion of the engines in an airplane. After describing the terms and concepts of power, jets, and rockets, the author describes the reciprocating engines. The description of diesel engines helps to explain why these are not used in airplanes. The discussion of the carburetor is followed by a discussion of the lubrication system. Lubrication is an important feature in the smooth functioning of aircraft, not only because of lubrication properties but because of its complementary role in cooling down the heat released in engines. The chapter on reaction engines describes the operation of the jet in theory and gives examples of how the different types of jet engines operate. Rocket engines are also explained briefly. The book is to be used for the Air Force ROTC program only. (PS)