Magnetism and Accelerator Based Light Sources : Proceedings of the 7th International School ‘‘Synchrotron Radiation and Magnetism’’ Mittelwihr (France) 2018 This open access book collects the contributions of the seventh school on Magnetism and Synchrotron Radiation held in Mittelwihr France from 7 to 12 October 2018. It starts with an introduction to the physics of modern X ray sources followed by a general overview of magnetism. Next light matter interaction in the X ray range is covered with emphasis on different types of angular dependence of X ray absorption spectroscopy and scattering. In the end two domains where synchrotron radiation based techniques led to new insights in condensed matter physics namely spintronics and superconductivity are discussed. The book is intended for advanced students and researchers to get acquaintance with the basic knowledge of X ray light sources and to step into synchrotron based techniques for magnetic studies in condensed matter physics or chemistry. Chapter 1 X ray sources at large scale facilities Chapter 2 Concepts in magnetism Chapter 3 Electronic structure theory for x ray absorption and photoemission spectroscopy Chapter 4 X ray dichroisms in spherical tensor and Green’s function formalism Chapter 5 Spintronics and synchrotron radiation Chapter 6 p wave superconductivity and d vector representation.