Combinatorics on words, or finite sequences, is a field that grew from the disparate mathematics branches of group theory and probability. In recent times, it has gained recognition as an independent theory and has found substantial applications in computer science automata theory and linguistics. This volume is the first to present a thorough treatment of this theory and includes discussions of Thue's square free words, Van der Waerden's theorem, and Ramsey's theorem. This volume is an accessible text for undergraduate and graduate level students in mathematics and computer science as well as specialists in all branches of applied mathematics.