Core-level Spectroscopy in Condensed Systems describes howrecent improvement of various experimental methods, togetherwith new light and x-ray sources, have provided freshinformation about the electronic states and atomicstructures of a wide variety of materials. The topicscoveredrange from the high-energy spectroscopy of bulkelectronic states of rare-earth and transition metals andcompounds, including high T superconductors, to recentdevelopments in photoelectron diffraction and other surfaceproblems, all with emphasis on theoretical aspects.