This volume is composed of notes from lectures given at the 40th Karpacz Winter School, which focused on Quantum Gravity Phenomenology
particularly its applications in astrophysics and cosmology. After several decades in which the quantum-gravity problem was studied in a way that did not involve at all the confrontation with experiments [1, 2], over the last few years the idea of testing quantum-gravity ideas using experimental
data has attracted significant interest. It was just around the time of the 35th Karpacz Winter School [3] that this change of attitude materialized in a part of the quantum-gravity community. And discussions that got started at the time of the 35th Karpacz Winter School finally led to the choice of topic of this 40th Karpacz Winter School.