We review the search for the standard Higgs boson, the Higgs bosons of the supersymmetric standard model, and Higgs bosons from a variety of other models at present and future colliders. i 1Ĥ j 2 in the superpotential;Ĥ 1 andĤ 2 are the Higgs superfields) and m 12 = 0, so electroweak symmetry breaking does not occur. Thus the Higgs-field vacuum-expectation values, v 1 , v 2 , are naturally of the same size as the supersymmetry-breaking scale. Supersymmetry also makes the presence of fundamental scalar fields natural, although the Higgs fields are not the superpartners of any of the known fermions.In supergravity grand-unified models, electroweak symmetry breaking arises "radiatively", that is by evolving the parameters of the Higgs sector (including the soft SUSY-breaking parameters) from the GUT scale down to the weak scale via the renormalization group equations [36]. Due to the large mass of the top quark, the parameter m 2 2 is driven more rapidly towards zero (often to negative values) than are m 2 1 and m 2 12 , so that S is driven negative at the weak scale, triggering electroweak symmetry breaking. Thus, in these models, electroweak symmetry breaking is explained by the large top-quark mass (more precisely, by the large top-quark Yukawa coupling). Supergravity models can also explain why the scale of supersymmetry breaking (i.e., the scale of the soft-supersymmetrybreaking terms) is comparable to the weak scale, rather than the GUT scale; this is a natural result if supersymmetry breaking occurs via a "hidden" sector.As in the general 2HDM, the presence of two Higgs-doublet fields implies that the spectrum of Higgs particles is much richer in the minimal supersymmetric model than in the standard model. However, the two-doublet MSSM is a highly constrained version of the general 2HDM. First, the two-doublet MSSM Higgs couplings are automatically type-II, with one Higgs doublet (H 1 ) coupling only to down-type quarks and leptons, and the other (H 2 ) coupling only to up-type quarks. Secondly, in the MSSM, CP conservation in the Higgs sector is automatic (for a review and references, see [16]), and we find the previously-mentioned five physical Higgs particles: two CP -even neutral scalars, h 0 and H 0 ; a CP -odd neutral scalar (often called a pseudoscalar), A 0 ; and a pair of charged Higgs bosons, H ± . Further, due to the special form of the potential, Eq. 4, dictated by softly-broken supersymmetry, the Higgs sector is described (at tree level) by just two free parameters, only one more than the standard Higgs model. It is conventional to choose the mass of the pseudoscalar Higgs boson, m A 0 , and the ratio of the Higgs-field vacuumexpectation values, tan β ≡ v 2 /v 1 , as the free parameters. Other parameters of the model affect the Higgs sector after including loop corrections [37]; the most important of these are the top-quark and the stop-squark masses, with parameters that influence stop-squark mixing also playing a significant role.The dominant radiative corrections arise from an incomplete cance...