Abstract We review the present status of the standard model of weak and electromagnetic interactions and of QCD, and examine the likely avenues of future development. The most attractive possibility is that there is a “grand unified theory” (GUT) which describes all known interactions except gravity, and in which the only input energy scale is the Planck mass. The GUTs so far proposed share the deficiency that they offer no explanation of the (≥ 3) observed fermion generations. We review the “horizontal” synmetries invented to bring order to the fermion sector. Typically such theories have non-minimal Higgs content, so we review the processes whereby charged or neutral scalars may be found. The incorporation of supersymmetry into the gauge theory of strong, weak and electromagnetic interactions is another attractive prospect and we discuss briefly the attempts to do this and the likely experimental signatures of such a scheme.