This book constitutes the refereed proceedings of FME '97, the 4th International Symposium of Formal Methods Europe devoted to Industrial Applications and Strengthened Foundations of Formal Methods , held in Graz, Austria, in September 1997. The 35 revised full papers presented in the volume were selected from a total of 94 submissions. Formal methods and mathematically based techniques are increasingly recognized as a viable technology for the development and engineering of computing systems. The majority of the papers in this volume describe industrial applications, extensions to existing techniques, or case studies; papers on theoretical aspects show clear potential applicability.