This volume and the accompanying CD-ROM cover the whole breadth of contemporary finite state language modeling, from the mathematical foundations to developing and debugging specific grammars. In addition to applications developed in the broad frameworks of the Xerox regular expression calculus or the AT&T/Bell Labs system of weighted transducers, finite state methods are shown to be useful in constraint-based or TAG-based systems, for machine translation, for information extraction, and for discourse analysis. The CD includes source code, documentation, and executables for several systems, including a faithful reconstruction of the very first finite state parser from 1959, high performance finite state toolkits, and a strikingly simple implementation of the basic ideas in hidden Markov modeling. The book is intended for students, software engineers, and researchers working in the area of natural language processing or computational linguistics.