This book deals with gasdynamic lasers (GDL)-high-energy sources of co- directional radiation. The theory and practice of gasdynamic lasers herent are based on three fields of modern science: quantum electronics, physico- chemical kinetics, and gasdynamics. This circumstance has determined the content of this book, which can be divided into two parts. The first four which occupy a considerable part of the book, prepare the reader chapters, for discussing the theoretical and experimental results of up-to-date GDL studies. The necessity of such a presentation is dictated by the fact that gasdynamic lasers can be a subject of interest for readers who are experts one of the mentioned fields, or those who have just begun studying in only GDLs. Such a representation is based on the experience gained by the author over several years in delivering lectures on this subject to students of Moscow State University. These lectures fonned the basis of the book, which can also be used as a text. The basic information on gasdynamic lasers is contained in the last two chapters of the book. These chapters give mathematical models of processes occurring in existing high-energy infrared GDLs (C0 GDLs, carbon monoxide 2 GDLs, etc. ), experimental results for these lasers, and also consider some possible new designs of GDLs. Of greatest interest in this respect are the attempts to create recombination electronic GDLs and plasmadynamic lasers.