Introduction -- PID Control and the Sequence of the Time -- Control Theory, Time Concepts and Calculus -- Sampling and Integral Sums -- On Reversibility -- Feedback: Mixing Memory and Desire -- Fourfold Vision. A Code.

Control Theory is an interdisciplinary field of engineering and mathematics that studies the behavior of dynamic systems with external stimuli and how to modify such behavior through feedback, and the very concept of dynamic system implies the study of how the trajectories of a point in a geometric space evolve in time. Thus, time is at the very foundation of control theory, and its development and achievements are conditioned both by the conception we have of it and by our way of measuring and using it. Following a quasi-chronological order, this work aims to give an overview of how these conceptions and these ways of measuring and using time are reflected in the paths followed by control theory from its origins to the present day.