This paper reviews the general analysis of electroweak vacuum polarization diagrams' contributions to precision experiments. It discusses the parameters S, T, and U, which summarize the effects of these diagrams. The paper shows that S can be computed using a dispersion relation and estimates S in technicolor models. It discusses the reliability and gauge invariance of this estimate and presents current experimental limits on S and T. The paper also discusses the implications of these parameters for different models of the Higgs sector and how they can be used to distinguish between them. It reviews the formalism of oblique corrections, including the Kennedy-Lynn parametrization, and shows how these corrections can be evaluated using dispersion relations. The paper also discusses the estimation of oblique corrections for strongly interacting Higgs sectors and the experimental constraints on S and T. It concludes that the parameters S and T are important for understanding the effects of new physics on electroweak interactions and that they provide a useful framework for interpreting experimental results.This paper reviews the general analysis of electroweak vacuum polarization diagrams' contributions to precision experiments. It discusses the parameters S, T, and U, which summarize the effects of these diagrams. The paper shows that S can be computed using a dispersion relation and estimates S in technicolor models. It discusses the reliability and gauge invariance of this estimate and presents current experimental limits on S and T. The paper also discusses the implications of these parameters for different models of the Higgs sector and how they can be used to distinguish between them. It reviews the formalism of oblique corrections, including the Kennedy-Lynn parametrization, and shows how these corrections can be evaluated using dispersion relations. The paper also discusses the estimation of oblique corrections for strongly interacting Higgs sectors and the experimental constraints on S and T. It concludes that the parameters S and T are important for understanding the effects of new physics on electroweak interactions and that they provide a useful framework for interpreting experimental results.