The compiler is one of the most important aspects of system software. When any computer user develops a computer program, one must use some programming language, rather than using a computer instruction set. This implies that there must be the compiler of the programming language that has been installed on the computer one uses, and otherwise the developed program cannot be run.

There are some differences between a compiler and programming language. Once language is designed, it must be kept unchanged (except when it contains a mistake that has to be corrected), while the techniques for implementing compilation might be changed over time. Hence people always explore the more efficient and more advanced new techniques to raise the quality of compilers.

The course similar to “The principles of Compilers” has become one of the most important courses in computer science within higher institutes. According to our knowledge, the development of compilation techniques evolves in two directions. One is towards the improvement of the compilation techniques for existing languages. Another is towards the research and development of the compilation techniques of new languages. These new languages include object-oriented languages, distributed languages, parallel languages, etc. This book introduces the newest knowledge in the field, and explores the compilation techniques suitable for the languages and computation. It associates the compilation of programming languages with the translation of natural languages in human brains so that the reader can easier understand the principles of compilers. Meanwhile, it introduces the algebraic method of compilation that belongs to formal technology.