This is the second book edited with a selection of papers from the two-yearly THIESEL Conference on Thermo- and Fluid Dynamic Processes in Diesel Engines, organised by CMT-Mvtores Termicos of the Universidad Po/itecnica de Valencia, Spain. This volume includes versions of papers selected from those presented at the THIESEL 2002 Conference th held on lOth to 13 September 2002. We hope it will be the second volume of a long series reflecting the quality of the THIESEL Conference. This year, the papers are grouped in six main thematic areas: State of the Art and Prospective, Injection Systems and Spray Formation, Combustion and Emissions, Engine Modelling, Alternative