This book constitutes the strictly refereed proceedings of the 11th European Conference on Object-Oriented Programming, ECOOP'97, held in Jyvaskyla, Finland, in June 1997.The book presents 20 revised full papers selected from a total of 103 submissions; also included are two full invited presentations and one abstract of an invited talk. The book is divided into topical sections on programming languages, types, metaprogramming, implementation and systems, formal methods and specifications, Java, and patterns. All in all, the volume impressively demonstrates that object-oriented technology has grown from a limited academic exercise to an industrial driving force.