This book is based on the monograph Acoustic Echo and Noise Control, which was published by Wiley (2004). The information has been revised and updated with important new information included. The book contains fundamental analysis of new topics such as bandwidth extension and speech enhancement by partial signal reconstruction. Emphasis is put on entire systems such as speech dialog systems and in-car communication systems. The latter record the speech of the driver and the passenger in a car, process these signals to get rid of background and feedback components, and finally play them back via loudspeakers located close to the backseat passengers.