This book constitutes the refereed proceedings of the 7th International Joint Conference CAAP/FASE on Theory and Practice of Software Development (TAPSOFT'97), held in Lille, France, in April 1997.The volume is organized in three parts: The first presents invited contributions, the second is devoted to trees in algebra in programming (CAAP) and the third to formal approaches in software engineering (FASE). The 30 revised full papers presented in the CAAP section were selected from 77 submissions; the 23 revised full papers presented in the FASE section were selected from 79 submissions.