This book has benefited greatly from the many exchanges I have had with Jean-Pierre Banâtre, a specialist recognized for his work on programming languages, parallel programming, software architectures and distributed systems. I had the chance to collaborate with him for more than 20 years, particularly in the management of research and development projects involving companies and public organizations.

Jean-Pierre Banâtre has given me friendly encouragement in this project, and I would like to express my gratitude to him here for his remarks, advice, encouragement and constructive criticism.