Marc Baus has been teaching the statistical mechanics course at the Faculté des Sciences of the Université Libre de Bruxelles in Belgium for several years. As a Directeur de Recherches of the Fonds National de la Recherche Scientifique, he has published more than a hundred research papers in the areas of plasma physics and phase transitions .Carlos F. Tejero has been professor of thermodynamics and statistical physics at the Facultad de Ciencias Fisicas of the Universidad Complutense de Madrid in Spain. As Investigador Principal he has directed various investigations in the field of phases of matter and soft matter. Both authors have collaborated for more than thirty years.