John Wills is a Technical Staff Member in the Theoretical Division at Los Alamos National Laboratory, current serving as Group Leader of the Physics and Chemistry of Materials Group. He has worked on electronic structure theory and application for the past 27 years, and is an author on 170 publications in this area, 61 of which are on the electronic structure of f-electron elements and compounds. Olle Eriksson has been active in the theory of electronic structure of materials for 25 years, and has published some 400 articles in this field. He is currently chair professor at the Department of Physics and Materials Science, Uppsala University. Per Andersson is currently Senior Scientist at the Swedish Defence Research Agency and has been active in the field for 15 years. Anna Delin has been active in the theory of electronic structure of materials for 15 years, and has published some 100 articles in this field. She is currently associate professor at the Department of Physics and Materials Science, Uppsala University. Oleksiy Grechnyev is has been active in the theory of electronic structure of materials and magnetism for 10 years, and has published 16 articles in this field (using name spelling A. Grechnev). He has graduated from Kharkiv National University (Ukraine) and obtained a Ph D degree in Uppsala University (Sweden). He is currently researcher at Department of Theoretical Physics, B. Verkin Institute for Low Temperature Physics and Engineering (Kharkov, Ukraine). Mebarek Alouani has been working on theory of electronic structure and spectroscopy for 26 years, and has published more than 100 articles and books in this field. He is currently full professor at the Institute of Physics and Chemistry of Materials of Strasbourg (IPCMS) of the University of Strasbourg, France.