Recent studies of the higher auditory system have reinforced the concept of parallel processing as an organisational strategy in all sensory pathways. Separate auditory pathways, having their origins in the cochlear nucleus, carry information leading to topographic representations of various sound parameters in higher nuclei. In addition to sound frequency, intensity and position have been shown to be mapped across various auditory system nuclei in some species. Complex sounds may also have a topographic organisation. The functional significance of these maps is presently unclear. The existence of some maps only at higher levels of the auditory system suggests that much of the organisational complexity of the system may be concerned with the analysis of acoustic parameters that are simply relayed through more peripheral auditory structures. However, sound frequency is mapped at every level of the system. The relationship between these representations of the auditory receptor surface and the other, centrally synthesised maps is currently an issue of intense research interest.