Abstract : The present paper deals with the life and some aspects of the scientific contributions of the mathematician René Gateaux, killed during World War 1 at the age of 25. Though he died very young, he left interesting results in functional analysis. In particular, he was among the first to try to construct an integral over an infinite dimensional space. His ideas were extensively developed later by Paul Lévy. Among other things, Lévy interpreted Gateaux's integral in a probabilistic framework that later contributed to the construction of the Wiener measure. This article tries to explain this singular personal and professional destiny in pre- and postwar France.