providing engineers, beginner or senior engineers with original tools and keys to understanding the social world in which they operate, this is the aim of this book. It is organised in leaflets, from A (‘collective action’) to W (‘Watteau or historicity’), and offers a sociological look at various problems or phenomena encountered by any engineer on a daily basis. These include: decision making, obedience, responsibility, trust, innovation, management requirements or sense of work. The aim of this book is thus to question the reader, rather than to provide solutions, to open up new horizons rather than ending controversy. With the help of photographs, literary extracts, examples from the world of culture and history, experience reports or field surveys, the author discovers his eyes and offers a different view on the social world, far from the ideas received and unique thinking. These sociology keys do not require a linear reading, as Voltaire stated at the preface of his handheld philosophical Dictionary, ‘wherever you open it, what to think about’.