We all are users of technology and services, but the way we use them strongly depends on who our 'interlocutor' is: a machine, a software application or a person. The contributions of this volume look at the concept of the user from various perspectives and continue to discuss the theme started in volume three on the user of the artificial. Topics include: man-machine relations such as the user and the virtual world of the internet or users in various cultural contexts of the artificial. The second part of the book focuses on man-nature relations and introduces the Japanese concept of "Kyosei "(symbiosis) in the context of technology and the environment.