This issue of Laser and Particle Beams includes papers presented at the “Workshop on Simulations of Ultra Intense Laser Beams Interaction with Matter” held in Bordeaux, France, from 14 to 16 April, 2003. This workshop was organized jointly by the Polytechnic University (Madrid, Spain), University of Bordeaux 1 (Talence, France), University of Milano-Bicocca (Milan, Italy), and Commissariat à l'Energie Atomique (CEA, France), sponsored by the European Science Foundation (ESF), University of Bordeaux 1, and CEA.