"At last, there is a comprehensive book on the cosmic microwave background radiation (CBR). What's more, it's a good one. Bruce Partridge's 3K: The Cosmic Microwave Background Radiation contains everything you need to get a solid foundation in this exciting and rapidly growing field. One of the pioneers, Partridge is still active in wrestling secrets from the CBR. His book summarizes the theoretical framework in which to interpret the measurements and gives a detailed account of the instrumentation and observations. It is clear, informative, and fun to read....Partridge has written a book that will be relevant for years to come." Lyman Page, American Journal of Physics