  The most significant results on hard scattering processes in Au+Au, p+p, and
d+Au collisions at sqrt(s_NN) = 200 GeV obtained after 3 years of operation at
the BNL Relativistic Heavy-Ion Collider (RHIC) are summarized. Hadron
production at high transverse momentum (p_T) in central Au+Au collisions shows
very different properties (production yields, flavor composition, azimuthal
correlations, ...) in comparison to p+p, d+Au, and peripheral Au+Au collisions,
and this fact constitutes arguably the most interesting outcome of the
experimental program so far. Four main topics are covered in this report: (i)
the depletion of high p_T inclusive hadron spectra, (ii) the ``anomalous''
baryon-meson composition at intermediate p_T's, (iii) the disappearance of
away-side azimuthal (jet) correlations, and (iv) the large value of collective
azimuthal (elliptic flow) correlations. Additionally, the observed high p_T
``Cronin enhancement'' in d+Au collisions will be discussed. A succinct
comparison of experimental data to theoretical models is also provided.
