Fully revised, the new Fourth Edition of An Introduction to Formal Languages and Automata provides an accessible, student-friendly presentation of all material essential to an introductory Theory of Computation course. The text was designed to familiarize students with the foundations and principles of computer science and to strengthen the students' ability to carry out formal and rigorous mathematical arguments. In the new Fourth Edition, author Peter Linz has offered a straightforward, uncomplicated treatment of formal languages and automata and avoids excessive mathematical detail so that students may focus on and understand the underlying principles. In an effort to further the accessibility and comprehension of the text, the author has added new illustrative examples throughout.