Twenty-five articles have been selected from the first 14 volumes of the "Séminaire de Probabilités", all out of print, for their historical and/or mathematical interest. Among the many articles devoted to Martingale theory in the early volumes of the Séminaire, we have chosen to reprint those that are particularly significant from a historical point of view, as well as those that can still be useful today. They are reprinted here verbatim, with a short retrospective comment, for the benefit of researchers in the theory of shastic processes, in mathematical finance, or in history of mathematics.