The most significant experimental results on hadron spectra at large
transverse momentum available at the time of Quark Matter 2004 conference are
reviewed. Emphasis is put on those measurements that provide insights on the
properties of the QCD media, ``Quark Gluon Plasma'' and ``Color Glass
Condensate'', expected to be present in nucleus-nucleus collisions at collider
energies.Comment: 2 plots updated. Minor changes in tex