From David Huron’s review of the book:
This massive tome is the culmination of more than two decades of research by one of the leading figures in auditory perception — Albert Bregman. Over the years, a constant series of papers has issued forth from Bregman’s Montreal lab — nearly all dealing with the formation of auditory images. In this book, Bregman has brought it all together and given us a lucid and masterful theory of how listeners make sense of the world of sound
Bregman begins by asking the question, what is the purpose of perception? He suggests that our perceptual faculties evolved as a means of allowing us to construct a useful representation of reality. Perception is functional and ecological — providing us with the what, when, and where of the events around us. The primary task of the auditory system is to arrange the cacophony of frequency wisps into meaningful clumps that correspond to various real-world activities. In short, the act of hearing may be likened to the work of a cartographer constantly drafting maps of the auditory scene.
Some sounds (such as the slamming of a door) mark the occurrence of unique events. But the world of sound is not merely a succession of momentary incidents. Even discrete sounds — such as a series of footsteps or the dripping of a tap — are often caused by an on-going coherent activity. Most sounds have a lineage or history. The mental images we form of such “lines of sound” Bregman has dubbed auditory streams, and the study of the behavior of such images is the study of auditory streaming. Since the recognition of events depends upon the proper assignment of auditory properties to different sound sounrces, auditory streaming is fundamental to the process of scene analysis — which in turn is fundamental to music perception.