Pierre Marty and Michel de M’Uzan first described “operational thinking” (pensée opératoire) at the Congress for French-Speaking Psychoanalysts in 1962. The Paris Institute of Psychosomatics (IPSO), a day hospital at the time, was founded by Simone Veil, then Minister of Health, in 1978. Pierre Marty, the Institute’s medical director, and Michel Fain were closely involved; the latter gave numerous seminars there, mainly theoretical, while Marty conducted consultations known as “psychosomatic investigations” and supervised all the treatments carried out at the Institute. The author reminds us of Marty’s oral teachings on the technique with patients who function in an “operational” mode.