Active Nitrogen focuses on the experimental and theoretical investigations on active nitrogen. Divided into five chapters, the book starts by giving an introduction to the discovery of active nitrogen, the energy content, and the methods by which this may be produced. The succeeding part deals with light emissions from active nitrogen system. This discussion includes molecular spectrum of nitrogen, emission from atomic energy and condensed active nitrogen, emission from molecular species with electronic energy levels below and above 9.76 eV, and light-emitting systems of active nitrogen. The next part focuses on theories on active nitrogen. The theories discussed are long-lived Lewis-Rayleigh afterglow and short-lived, energetic afterglows. Numerical representations are provided to test the validity of the theories. Lastly, the discussions end with chemical reactions of active nitrogen. Topics contained in this part are text on recombination of N(4S) atoms; rate constants for reactions presumably induced by direct N(4S) attack; reactions caused by excited nitrogen molecular attack; and mechanism for reactions of active nitrogen that seem to influence direct N(4S) attack. The book is a valuable source of information for readers interested in the research on active nitrogen.