This book systematically introduces the concepts and methods of intelligent science, incorporating research results from brain science, cognitive science, artificial intelligence, information science, formal systems, philosophy, etc., and exploring the mechanisms and laws of natural intelligence and machine intelligence. This book can be used as a textbook for senior undergraduate and graduate courses in Intelligent Science, Cognitive Science, and Neuroinformatics. And it can also serve as a reference book for researchers working in the fields such as intelligent science, artificial intelligence, cognitive science, brain science, neuroscience, and psychology.