The dream of a direct electronic analogue for a biological nose may still be some way from realisation, but considerable progress can be reported towards prototype computerised instruments capable of equivalent, or even better, performance in certain applications. The achievements are partly attributable to success in new circuit and systems approaches, as well as in developing sensing devices, with the prospect of further rapid progress based on the exploitation of materials and integrated sensor technology. Other important advances are being created in information processing, particularly in relation to pattern recognition.