This two-volume set is the seminal classic of analysis of sound in closed spaces: rooms, auditoriums, concert halls and churches. This book set was originally written in German by the world-recognized acoustician, Lothar Cremer, in collaboration with the eminent physicist, Helmut A. Müller. Later, they were brilliantly translated to English by Theodore J. Schultz. Together, the two volumes constitute the analyses of sound in a room from three modeling standpoints: geometrical acoustics, statistical acoustics, and wave acoustics. Setting forth three different views of the same phenomenon provides the reader with broadened understanding and valuable insights in to the entire process of sonification. Painstakingly careful cross-referencing guides the reader back and forth among the alternative analyses and reinforces understanding. Volume 1 addresses Geometrical Room Acoustics, Statistical Room Acoustics, and Psychological Room Acoustics; Volume 2 addresses Wave-Theoretical Room Acoustics. Together, the two volumes constitute a foundation for acoustic analysis for acousticians, architects, civil engineers and those interested in room acoustics as performers or listeners. The two volumes total 1100 pages with 13 tables and 325 illustrations.