This conference is part of the series initiated in 1973 in Paris, as an International Colloquium on Photon-Photon Collisions at Electron-Positron Storage Rings.

The scientific program will include topics related to photon-photon and photon-hadron collisions as well as final-state photon production at current and future colliders. In addition, high-energy astrophysics gamma-rays, and photon-related searches of new physics (axions, dark/hidden photons, ...) will also be discussed. The conference format consists of talks in plenary sessions only. The LOC offers a number of young researcher grants to attend the conference. Interested participants are invited to send an e-mail to photon19_loc@lists.lnf.infn.it with their motivated request for support.