Discovering supersymmetry with electron and photon beams

Linear collider designs are optimized for e+e- collisions. However, from the physics point of view, linear colliders may also be advantageously operated in an e-e-, e-γ or γγ mode. These options, which have not been available up to now, will provide unique tests of the standard model and of physics beyond it. As an example, we review the prospects for discovering and studying supersymmetry at linear colliders in e-e-, e-γ and γγ collisions. In particular, we argue that e-e- scattering is much better suited than e+e- annihilation for discovering selectrons or charginos. (orig.)