Nantes is proud to welcome the 20th edition of the ECOOP (European Conference on Object Oriented Programming) Conference Series. ECOOP aims at bringing together people from various countries, industrial and academic, interested in a wide spectrum of technologies related to object-oriented area. The ECOOP conference lasts for a week. It includes plenary sessions, which take place the last three days of the conference, whereas monday and tuesday are dedicated to numerous workshops and tutorials.