The book, Theory of Parsing, Translation and Compiling, by Alfred V. Aho, and Jeffrey D. Ullman, is intended for a senior or graduate course in compiling theory. It is a theoretical treatment of a practical computer science subject. Since computer science is an ever changing area of study, this book emphasizes ideas, rather than specific application details. The algorithms and concepts presented in the book should survive to new generations of computer technology, programs and systems. Numerous examples are given, with specific context, rather than on the large complicated contexts normally found in implementations, even in cases where the theoretical ideas are difficult to understand in isolation.