RESOLVED PHOTON PROCESSES

We review the present level of knowledge of the hadronic structure of the photon, as revealed in interactions involving quarks and gluons 'i n' the photon. The concept of photon structure functions is introduced in the description of deep-inelastic e gamma scattering, and existing pammetrizations of the parton densities in the photon are reviewed. W e then turn to hard gamma p and gamma gamma collisions, where we treat the production of jets, heavy quarks, hard (direct) photons, J/psi me sons, and lepton pairs. We also comment on issues that go beyond pertu rbation theory, including recent attempts at a comprehensive descripti on of both hard and soft gamma p and gamma gamma interactions. We conc lude with a list of open problems.