Building from the stochastic modeling of physical systems, we address collective effects specific to the nonequilibrium nature of the dynamics, mostly in classical systems, but also in quantum ones. Our walk begins with a landmark result in nonequilibrium statistical mechanics that tells us that fluctuations even far from equilibrium, possess intriguing statistical properties inherited from microscopic reversibility. Relaxation towards equilibrium, possibly in the vicinity of a critical point, and then the build-up of correlations in driven systems (with the possibility of phase transitions down to one space dimension) make up the first half of the lectures. We then embark in the modeling of population dynamics (from chemical reagents to living matter) and conclude the lecture series with phenomena and modeling specific to the nonequilibrium quantum realm. Along the lectures, we map these faces to names and physical phenomena. They’ll all be familiar to the audience by the end of the course.