Leaving aside the obvious worth of knowledge, the terminology, notations and techniques of computer theory are necessary in teaching Computer Design, Artificial Intelligence, the analysis of algorithms and so forth. Of all programming skills that students learn, two of the most important things are the abilities to recognize and manipulate context-free grammars and to understand the power of recursive interaction of parts of procedures. In order to have sound foundation, each advance course has to begin at the level of defining rules of productions and derivations. Any career that might be pursued by a Computer Science graduate will make significant use of subject matter of this book.