  A review of searches for physics beyond the Standard Model carried out at
high energy lepton-hadron and hadron-hadron facilities is presented, with
emphasis on topics of interest for future data taking at the upgraded Tevatron
$p{\bar p}$ and HERA $ep$ colliders. The status and discovery prospects are
discussed for leptoquarks, Technicolour and supersymmetry, forbidden lepton and
quark flavour-changing processes, extra gauge bosons, excited states of
composite fermions, generic contact interactions and extra compactified
dimensions.
