Pythagoras believed that Numbers rule the universe . This is indeed the case nowadays when numbers are vital to science, economics, sports, education, and many aspects of everyday life. How do we understand numbers? Do animals and babies have numerical abilities? Why some people are failed to grasp numbers, and how we can improve numerical understanding? These questions and much more are covered in this unique handbook that integrates several disciplines including different branches of psychology, education, and neuroscience. It provides a comprehensive understanding of numerical cognition in more than 60 chapters that are written in an accessible form for scholars and students, as well as educationalists, clinicians, and policy makers. After reading the book, you might not be Pythagoras or Einstein, but you will agree that numbers rule the universe.