We are surrounded by noise‎;‎ we must be able to separate the signals we want to hear from those we do not‎.‎ To overcome this 'cocktail party effect' we have developed various strategies‎;‎ endowing computers with similar abilities would enable the development of devices such as intelligent hearing aids and robust speech recognition systems‎.‎ This book describes a system which attempts to separate multiple‎,‎ simultaneous acoustic sources using strategies based on those used by humans‎.‎ It is both a review of recent work on the modelling of auditory processes‎,‎ and a presentation of a new model in which acoustic signals are decomposed into elements‎.‎ These structures are then re‎-assembled in accordance with rules of auditory organisation which operate to bind together elements that are likely to have arisen from the same source‎.‎ The model is evaluated by measuring its ability to separate speech from a wide variety of other sounds‎,‎ including music‎,‎ phones and other speech‎.‎