Aristotle's convincing philosophy is likely to have shaped (even indirectly) many of our current beliefs, prejudices and attitudes to life. This includes the way in which our mind (that is, our capacity to have private thoughts) appears to elude a scientific description. This book is about a scientific ingredient that was not available to Aristotle: the science of information. Would the course of the philosophy of the mind have been different had Aristotle pronounced that the matter of mind was information? This "mind is information" assertion is often heard in contemporary debates, and this book explores the verities and falsehoods of this proposition.