Two Nobel Laureates present a systematic, comprehensive account of the theory, techniques, experimental data, and interpretation involved in the study of microwave spectroscopy -- a subject relevant to nuclear physics, molecular structure, chemical kinetics, quantum electrodynamics, and astronomy.The material in this volume is discussed critically, systematically, and in the simplest form. The simplicity of the wording and mathematics makes most of the contents accessible to those with a very elementary knowledge of quantum mechanics and atomic physics. Although the treatment is continuously developed, each of the 18 chapters is self-contained. Nearly 200 tables and figures augment the text. Appendixes supply most of the background for research and interpretation of microwave spectra; they also contain extensive data on nuclear and molecular constants, including essentially all those determined by microwave techniques. 'Equally suitable for use as a fundamental reference or advanced textbook.' -- 'U.S. Quarterly Book Review.' Here two Nobel Laureates present a systematic, comprehensive account of the theory, techniques, experimental data, and interpretation involved in the study of microwave spectroscopy.