The chemistry of the upper atmosphere is developing very rapidly as a scientific field. More and more specialists in the field of atmospheric physics, radio wave propagation, rocket and satellite investigations, etc., are concluding that a complete understanding of phenomena in the earth’s upper atmosphere requires a detailed investigation of elementary processes, particularly chemical and photochemical processes. On the other hand, it is a demonstrated fact that more and more leading specialists (physicists engaged in laboratory experiments in the field of chemical kinetics, plasma physics, electron and ion collisions, etc.) are manifesting interest in study of problems associated with elementary processes in the upper atmosphere. This promises a still more vigorous development of atmospheric chemistry in the immediate future and probably the solution of a number of problems mentioned in this book for which no final solution has yet been obtained.