This book constitutes the refereed proceedings of the 17th Annual Symposium on Theoretical Aspects of Computer Science, STACS 2000, held in Lille, France in February 2000. The 51 revised full papers presented together with the three invited papers were carefully reviewed and selected from a total of 146 submissions on the basis of some 700 reviewers' reports. The papers address fundamental issues from all current areas of theoretical computer science including algorithms, data structures, automata, formal languages, complexity, verification, logic, cryptography, graph theory, optimization, etc.