This fourth edition of the Air Force Handbook of Geophysics and the Space Environment has been completely revised. It begins with chapters on the sun and its emissions, then treats the earth's magnetic field and the radiation belts, and follows with chapters on the ionosphere and the aurora. The subject of electrical charging of space vehicles has been of special concern to the Air Force and has been included to aid the designers interested in that problem. The next group of chapters deals with properties of the atmosphere, and the handbook concludes with chapters on the earth sciences and infrared astronomy.