Simondon, Gilbert (1924—89) French philosopher of technology and society. His work is championed by his friend Deleuze, Gilles, and it has been influential in the formation of new materialism, but due to a lack of translations his work is relatively little known in Anglophone circles. However, the appearance of new translations of his major works is likely to change that situation. As a student, he studied philosophy, psychology, and physics, a fact reflected in his later work, especially his most important book Du Mode d’existence des objets techniques (1958), translated as On the Mode of Existence of Technical Objects (2017). Simondon’s work was primarily concerned with ontology, specifically the problem of individuation, not just how individuals emerge out of a particular milieu but also why they exist. In L’Individuation à la lumière des notions de forme et d’information (1964), Simondon argued that one cannot explain the individual by the milieu nor the milieu by the individual, and that one cannot reduce the one to the other. Individuation presupposes a metastable state of being, a field of pre-individual existentialism rich in potential, out of which the individual emerges in much the same way that crystals emerge from media.