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 Combustion Concepts and Experimental Techniques. The actual conference covered a wider scope of topics, including Air Management and Fuels for Diesel Engines and a couple of papers included reflect this variety. However, the selection of papers published here represents the most current preoccupations of Diesel engine designers, namely how to improve the combustion process using new injection strategies and alternative concepts such as the Homogeneous Charge Combustion Ignition.