One of the most spectacular discoveries of molecular astronomy has been thedetection of maser emission. The same radiation that is generated in thelaboratory on... » 

One of the most spectacular discoveries of molecular astronomy has been thedetection of maser emission. The same radiation that is generated in thelaboratory only with elaborate special equipment occurs naturally ininterstellar space. This intense radiation probes the smallest structures thatcan be studied with radio telescopes. By a fortunate coincidence maserradiation is generated in both star forming regions and the envelopes of latetype stars. The early and late stages in the life of a star are considered tobe the most interesting phases of stellar evolution. Maser emission has alsobeen detected in external galaxies. br This book provides an extensivecoverage of the interstellar maser phenomenon. A precondition for maser actionis departure from thermal equilibrium. The book therefore starts with adetailed coverage of the basic background concepts required for anunderstanding of line formation and radiative transfer. It goes on to describethe theoretical and phenomenological aspects of interstellar masers theirformation sites and the inversion mechanisms. br The book will interest activeresearchers in astronomy and astrophysics as well as in other areas of physics.It is suitable as a textbook in a graduate course and will enable a graduatestudent to embark on research projects in this exciting area in particular andmolecular radio astronomy in general. br «