  We review the realization of the Brout-Englert-Higgs mechanism in the
electroweak theory and describe the experimental and theoretical constraints on
the mass of the single Higgs boson expected in the minimal Standard Model. We
also discuss the couplings of this Higgs boson and its possible decay modes as
functions of its unknown mass. We then review the structure of the Higgs sector
in the minimal supersymmetric extension of the Standard Model (MSSM), noting
the importance of loop corrections to the masses of its five physical Higgs
bosons. Finally, we discuss some non-minimal models.
