A visitor from the mild climate of the UK to Rochester, New York State, in the middle of summer, receives a sensory shock. Apart from being much, much warmer, the visceral impact is huge. The light is brighter, the colouring of the birds is dramatic and the scent of the trees and plants is just so strong. At night the circadias are almost deafening. The information about the world gathered by sensory systems is the core idea this book will explore.

It so happens that Rochester is the home of Eastman Kodak and other major imaging companies such as Xerox and Bausch and Lomb, the place where a lot of important research on image physics, capture and storage took place. Images have played a part in human culture since the earliest cave paintings, but as computers have got faster, dynamic images, from mobile phones to giant plasma displays increasingly dominate our lives. Reproduced sound has gone beyond the radio to the ubiquitous MP3 player, seen on countless commuters, runners and diverse workers. But there are other senses, not yet so widespread in the artificial world. This book lies at the interface of the sensory biological world and man-made systems. It also projects forward to new computer interfaces and virtual environments not far down the track.

The senses of many animals, especially human beings, are very powerful general purpose information-seeking systems. A cat soon learns to recognise the sound of metal on metal of tin opener on tin or the sheepdog the distinctive whistle from which he receives his instructions.