This volume entitled "European Computational Aerodynamics Research Project (ECARP)" contains the contributions of partners presented in two work­ shops focused on the following areas: Task 3 on Optimum Design and Task 4.2 on Navier Stokes Flow algorithms on Massively Parallel Processors. ECARP has been supported by the European Union (EU) through the Indus­ trial and Materials Technology Programme, Area 3 Aeronautics, with the Third Research Framework Programme (1990-1994). Part A of this volume is focused on computational constrained optimization as a follow up of the EU research project" Optimum Design in Aerodynamics" , (AERO-S9-0026) dealing with more viscous flow based real applications. It pro­ vides the reader with a set of optimization tools and referenced data useful in modern aerodynamic design. Task 3 of the project entitled "Optimum Design" brought together 13 Euro­ pean partners from the academic and industrial aeronautic oriented community showing state of the art expertise in traditional automated optimization software on current computer technology to improve the capability to optimize aircraft shapes.