Abstract: The aim of this introductory talk is to illustrate how kinetic theory is used to investigate collective behaviour. Particularly, I will introduce the Vicsek model and Vicsek-related models. In the Vicsek model agents have a constant speed while trying to move in the same direction as their neighbors. The goal is to derive continuum/fluid-like equations from the discrete dynamics of the system. This derivation corresponds to linking microscopic and macroscopic phenomena.