The book of changes, I Ching.
The great charm of the book of changes lies in the fact that, by using axiomatized method, that is, starting from the earliest primitive concepts and a few self-evident axioms and postulates, by deductive reasoning, it has worked out all the inherent theorems of mankind under the guidance of the world outlook of unity of heaven and mankind.
It is just by relying on such a logical system derived from the numbers of the heavenly way that the traditional culture of China was able to transcend the boundaries of its time and place.