Proposal: this book is not for those interested in the theory of numerical computation, instead it is for professionals, engineers, scientists and the alike, whose goal is use various numerical algorithms, as tools in the tool box, to solve practical problems. Although the mathematical theory may not be their ultimate concern, they still need to know not only what methods they should use to solve their problems, but also why they work, and how to use them correctly and effectively. For such reasons, they also need to know the mathematics behind the methods. Besides, some practicing engineers may still be curious enough to want to know why, in addition to what and how, while using the numerical algorithms to solve their problems. They deserve the oppotunity of opening the black box to learn the inner workings of such methods, to quench their thirst of curiosity for the mathematics hiden inside the software package they use.