One of the founders of the Service de Physique Théorique de Saclay in the early sixties, Roger Balian is still one of its most eminent members. Head of the SPhT from 1979 to 1987, member of the French Académie des Sciences, former student and Professor at Ecole Polytechnique, former Director of the Les Houches Physics School, he authored well known teaching books. Roger is famous for the Balian-Low theorem, the Balian-Bloch semiclassical expansions, the discovery of the B-Phase of superfluid He3, his works in nuclear physics and the N-body problem, on the Casimir effect, on irreversibility and entropy in statistical mechanics, etc. As active as ever, Roger is presently interested in the measurement process in quantum mechanics. Happy birthday Roger!