Resolved Photon Processes

We review high--energy scattering processes that are sensitive to the hadronic structure of the photon, describing theoretical predictions as well as recent experimental results. These processes include deep--inelastic electron--photon scattering at \eplem\ colliders; and the production of jets, heavy quarks and isolated photons in the collision of real photons at \eplem\ colliders, as well as in photon--proton collisions at $ep$ colliders. We also comment on ``minijet'' based calculations of total $\gamma p$ and \gamgam\ cross--sections, and discuss the possibility that future linear \eplem\ colliders might produce very large photon fluxes due to the ``beamstrahlung'' phenomenon; in the most extreme cases, we predict more than one hadronic \gamgam\ event to occur at every bunch crossing.