This volume contains the proceedings of ICALP 89, held at Stresa, Italy, July 11-15, 1989. ICALP 89 is the 16th International Colloquium on Automata, Languages and Programming in a series of meetings sponsored by the European Association for Theoretical Computer Science (EATCS). It is a broadly based conference covering all aspects of theoretical computer science including topics such as computability, automata theory, formal language theory, analysis of algorithms, computational complexity, mathematical aspects of programming language definition, logic and semantics of programming languages, foundations of logic programming, theorem proving, software specification, computational geometry, data types and data structures, theory of data bases and knowledge based systems, cryptography,