We present our unified Lewis acid -base approach to adhesion and solvation at the liquid-polymer interface. This approach is to complement the original methodologies proposed by Fowkes and by van Oss, Chaudhury and Good (VCG). Intermolecular interactions are primarily dominated by dispersion, d, hydrogen bonding, h, and secondarily affected by orientation, o, and induction, i. Generally, the polarization component, p, represents both i and o interactions. Fowkes suggested that the acid -base component, -Yb, of the surface tension should consist of both h and p interactions. However, VCG proposed that the acid-base components, gamma (ab), result solely from hydrogen bonding, gamma (h), that is equivalent to 2(gamma (1) gamma )(1/2), where gamma (1) and gamma are the two hydrogen bonding parameters. VCG defined gamma (LW) as the Lifshitz-van der Waals component consisting of d, o and i contributions, thus, surface tension, gamma, equals, gamma (ab) (VCG)+gamma (LW). Both Fowkes and VCG assumed that the polar interactions for a liquid on a low energy surface are negligible. Now, we assume otherwise, and we treat the specific acid-base interaction to be hydrogen bonding. In addition, we also take into account the nonspecific polarization, p, interaction in terms of the equilibrium spreading pressure, pi (e), resulting from the adsorption of a liquid vapor on the polymer surface. Thus, our unified approach uses the dispersion component, gamma (d) of Fowkes, the hydrogen bonding, h, of VCG and the polarization, p, in terms of pi (e). The difference between the initial (theoretical) and equilibrium (experimental) surface tensions is pi (e), and others have observed that pi (e) on some polymers is substantial. The determination of several initial surface tensions of polymers by considering the effect of polarization is discussed. In the Appendix, we shall illustrate that this polar component, pi (e), is equivalent to the LESR polarity-dipolarity parameter, Pi*, (represented by the same symbol but in different context) for the solvatochromic treatment. Furthermore, the surface tension components, gamma (d), gamma (+), gamma (-) and pi (e), are now somewhat comparable with the four parameters in the original Taft-Kamlet relationship, delta, alpha, B, and Pi*. Thus, our proposed unified approach may finally help elucidate the long-debated Lewis acid -base theories pertaining to adhesion and solvation of polymers.