The School is devoted to the many-body physics of photon and polariton gases. This emerging field is relevant for systems with controllable photon-photon interactions, including nonlinear optical microstructures, superconducting quantum circuits, opto-mechanical resonators and atomic cavity QED networks. Photon and polariton gases also constitute a very promising platform for quantum simulation in the area of Quantum Technologies. The main objective of the school is to facilitate the exchanges and collaborations between people from different fields related to many-body physics.