The interest in e/sup +/e/sup -/ experiments at LEP energies

A review is presented of various open theoretical questions and how LEP experiments may help answer them. Besides the conventional gauge theories of the strong, weak and electromagnetic interactions, LEP should also provide us with useful information relevant to grand unified theories, supersymmetry and dynamical symmetry breaking. New emphasis is laid on toponium as a laboratory for studying the weak interactions as well as the strong, and on the possibilities for testing technicolour at LEP. (60 refs).