Quantum Beam Science (ISSN 2412-382X) is an international scientific, peer-reviewed, open access journal on research derived from beam line facilities and related techniques published quarterly online by MDPI. The first issue was released in June 2017. The journal covers the following topics within the context of quantum beam science: *Quantum beams: synchrotron radiation X-rays gamma rays neutron scattering free electron lasers muons positrons electron scattering high-strength lasers protons, ions extremely strong lasers *Applications: materials science soft condensed matter hard condensed matter materials under extreme conditions high pressure, high temperature, warm dense matter radiation damage quantum states, Bose-Einstein condensates, low temperature dynamics of materials density of states diffusion, phonons, magnons, excitons kinetics of materials, chemical reactions, catalysis phase transformations crystalline, charge and magnetic structure protein crystallography amorphous materials, glasses, liquids, gasses engineering applications (strain, stress, texture, fatigue) in-situ, real-time observations bulk, surfaces, interfaces, atomic layers *Instrumentation: facilities, sources beamlines sample environment quantum beam optics computing combination of quantum beams data analysis *Fundamentals: quantum beam interactions interferometry fundamental optics cross sections scattering theories complementarity of different quantum beams