A faith in the coherence of the living world

In this review, I compare the development of Monod's intellectual leadership in two fields, the regulation of enzyme biosynthesis and the control of enzymatic activity. I characterize the comings and goings between his scrupulous analysis of a given model system, his ability to compare the outcome with very distant experimental results, his audacity in formulating, then a physical interpretation of this convergence through a unifying mechanism. Finally, I briefly discuss how his attitude has durably impacted the whole field of molecular biology.