The twelfth Advanced Study Institute (ASI) on Techniques and Con­ cepts of High Energy Physics was held at the Hotel on the Cay in St. Croix, U.S. Virgin Islands in June 2002. The Institute attracted 11 lecturers and 42 advanced PhD students and recent PhD recipients in experimental particle physics from 14 different countries. The scientific program covered a broad sweep of topics that are expected to remain of interest for many years to come. The topics in this volume complement those in earlier volumes (published by Kluwer) and should be of interest to many physicists. The main financial support for the Institute was provided by the Scientific Affairs Division of the North Atlantic Treaty Organization (NATO). The Institute was eo-sponsored by the U.S. Department of Energy (DOE), the Fermi National Accelerator Laboratory (Fermilab), the U.S. National Science Foundation (NSF), the Florida State Univer­ sity (FSU) - Offices of the Provost and the Dean of Arts and Sciences, the Department of Physics and the FSU High Energy Physics Group - and the Institute for Theoretical and Experimental Physics (ITEP, Moscow).