Mathematical models play an important role in many areas of socio-economics. One aim of this course is to demonstrate that mathematics has a part even in a somewhat "exotic" area, i.e. the control of illicit drug consumption. The main goal is not only to learn the modelling of dynamical systems (in particular, drug epidemics), but also to get acquainted with the main principles used for finding the optimal controls in the context of illicit drug use (i.e., to find the optimal prevention, treatment, and enforcement mix).