We would like to express our gratitude to all the authors who, despite their responsibilities, have agreed to write articles for a wide audience. This effort of pedagogy and popularization is not easy for researchers used to publish their work in journals intended for other scientists. Their contributions were solicited by the heads of the various sections, then evaluated by members of the editorial committee, without whom this digital encyclopedia would not exist; they are all warmly thanked. We would also like to thank the experts consulted, whether they were specialists who agreed to check the accuracy of the explanations provided, or teachers from the Académie de Grenoble who evaluated the pedagogical qualities of the articles. Finally, we would like to thank the journalists of the agency Technoscope, Isabelle Belin and Jean-Philippe Braly, for their careful review of most of the articles.

Many dozens of research laboratories and partner organizations have agreed that their staff should devote part of their time to this encyclopedia and illustrate the articles with photographs that they own. We would like to express our gratitude to them.

To the agency Groupe Curious which designed and developed this encyclopedia and to all those who helped to format the manuscripts, we would also like to express our sincere thanks. If this encyclopedia has an attractive aspect and a real coherence, it is thanks to all these people, among whom we would like to highlight the dedication of our webmaster, Diane Gaillard, then Marion Gueydan, and the generous participation of Alain Herrault and the collective Diverticimes, photographers.

Since its inception, our editorial initiative has constantly benefited from the expertise of Jean Bornarel, director of Grenoble sciences, whom we would like to thank. We are grateful to the Université Grenoble Alpes for having included this encyclopedia in the range of its publications now gathered in UGA editions, under the scientific direction of Romain Lajarge and editorial of Ilka Milanov. Within UGA editions we also thank Laurent Riou, head of the STM sector (Science, Technology, Medicine) and Lucie Delefosse for their support.

René Moreau and Joël Sommeria, editorial managers