In this provocative and ground-breaking book, Keith Devlin argues that in order to obtain a deeper understanding of the nature of intelligence and knowledge acquisition, we must broaden our concept of logic. Classical logic, beginning with the work of Aristotle, has developed into a powerful and rigorous mathematical theory with many applications in mathematics and computer science, but it has proved woefully inadequate in the search for artificial intelligence. The new kind of logic, also mathematically based, outlined by Professor Devlin is the culmination of collaborative research among some of the world's leading logicians, philosophers, linguists, psychologists, and computer scientists. It introduces the concepts of infon, a quantum of information, and situations, a dynamical generalization of sets, and is capable of handlng the issues involved in human communication, thought, speech, and machine information processing.