[en] This collective publication proposes a comprehensive synthesis on instruments, methodology, applications and works in which the interaction between X rays and condensed matter is implemented. This fourth release mainly focuses on the use the synchrotron radiation which is largely used by scientists to explore matter in new directions. After a presentation of X ray sources and of the issue of coherence, the chapters address some specific issues: small angle scattering of X rays, the EXAFS (Extended X-ray Absorption Fine Structure) as a local synchrotron technique, the state of art and evolution of X ray tomography in 2012, structural studies of complex ordered states in material science, studies of relationships between structures and properties in oxide ion based conducting materials, the possible explanation and prediction of recrystallisation from the characterization of the deformed state, and the applications of X rays to the study of metallic contaminants in the environment