In this book, the Zhou-Yi and its Divination Process are reviewed from mathematical perspectives which provide a completely new understanding of its meaning and operation features. The highlights are:- 1. The Generalized Yi Systems Group consists of an infinite number of Yi Systems, Zhou-Yi is just one item of the Yi System 2 in the Generalized Yi Systems Group. 2. Parameters of all Yi Systems can be conveniently found by a set of formulae. 3. The divination process of Zhou-Yi was written in a mnemonic format with hints for the steps of divination. The so called Biggest Computation Number is actually a dummy created to facilitate the counting of steps from Step 1. The actual number that affects the divination is given by subtracting 1 from the Biggest Computation Number as a hint for step 1. 4. Data from digital computer simulation of Zhou-Yi divination process show that in swapping the Yin-Yang Divined Numbers in a Line of a Yi Hexagram, the 6/9 swap is mathematically more logical than that of 7/8 swap. 5. Mathematically classified Trigram Groups and Hexagram Groups provide a new and more logical insights to the inter-relationships between the Diagrams.