The extreme point of penal justice under the Ancien Regime was the infinite segmentation of the body of the regicide: a manifestation of the strongest power over the body of the greatest criminal, whose total destruction made the crime explode into its truth. The ideal point of penality today would be an indefinite discipline: an interrogation without end, an investigation that would be extended without limit to a meticulous and ever more analytical observation, a judgment that would at the same time be the constitution of a file that was never closed, the calculated leniency of a penalty that would be at the same time the permanent measure of a gap in relation to an inaccessible norm and the asymptotic movement that strives to meet in infinity. The public execution was the logical culmination of a procedure governed by the Inquisition. The practice of placing individuals under ‘observation’ is a natural extension of a justice imbued with disciplinary methods and examination procedures. Is it surprising that the cellular prison, with its regular chronologies, forced labour, its authorities of surveillance and registration, its experts in normality, who continue and multiply the functions of the judge, should have become the modern instrument of penality? Is it surprising that prisons resemble factories, schools, barracks, hospitals, which all resemble prisons?