Imagine a banana. What colour is it? Yellow, of course. Now try to form a picture of one that doesn't exist, that can't exist: a blue banana with red spots. Imagine that. How did you do? If you found it hard, perhaps you ought to know that Igor Aleksander has a machine which can do that easily. When he asks it (in words) to produce an image of 'banana' that is 'blue with red spots', the image swims on to the screen in seconds. The idea of such a conscious machine seems absurd and almost heretical, and its advocates are often accused of sensationalism, arrogance or philosophical ignorance. Part of the problem is that consciousness remains ill-defined: many people argue that it will always lie beyond the remit of science, in the realm of philosophical speculation, too mysterious and complex for human understanding. Aleksander, a world leader in the field of artificial intelligence, now attempts to unravel these arguments dispassionately for a general audience and provide a rigorous definition of consciousness. He shows how the latest work with artificial neural systems suggests not only that an artificial form of consciousness is possible but also that its design would clarify many of the puzzles surrounding the concept. A centrepiece of the book is Magnus, the author's 'conscious' computer program. But the book also looks at the representation of 'self' in robots, the learning of language, and the nature of abstract concepts such as emotion, will, instinct and feelings. The book is more than a comprehensive survey of modern ideas and research. It also provides a cultural history of the field, putting in broader context the work of pioneering scientists and philosophers.