Higgs-physics phenomenology is one of the most important topics in particle physics today. Understanding the origin of the masses of the known particles in the universe is likely to dominate European research in high energy physics for the forseeable future. This proposel suggests two parallel paths for a phenomenological investigation of the broken symmetry sector of the electroweak theory. One approach is concerned purely with Standard Model predictions for the Higgs-signal. In particular, the next to leading order contributions from polarized e+/- and pp beams to the helicity dependent production amplitudes for photon-photon and gluon-gluon fusion will be calculated. On the other hand it is necessary to also include models encompassing the Glashow-Weinberg-Salam model. For the presently most attractive of those, the minimal supersymmetric extension, the next to leading corrections to the decay branching ratios and production cross sections will be calculated. All the above mentioned contributions are needed to allow for unambiguous signal identification and background subtraction in the face of expected low production rates.