2004 European School of High-Energy Physics: Barcelona, Spain 30 May - 12 Jun 2004

The European School of High-Energy Physics is intended to give young experimental physicists an introduction to the theoretical aspects of recent advances in elementary particle physics. These proceedings contain lectures notes on the Standard Model, quantum chromodynamics, flavour physics and CP violation, an introduction to physics beyond the Standard Model, neutrino physics, cosmology and astrophysics, as well as reports on quark deconfinement and nuclear collisions, accelerators for high-energy physics, and the scientific programme of the Joint Institute for Nuclear Research.