Historically, the Air Force has been the first involved in the nuclear deterrence mission. For over 40 years France’s Strategic Air Forces (FAS) have assumed this mission with a now legendary rigour. That has never prevented them, quite the contrary, from continuously adapting to the geostrategic environment, national defence policy, technological change and of course financial constraints. And the secret of their ability to adapt while assuring a credible deterrence, as described in this brief portrait by the twentieth officer to command them, has been that rigour.