The main paradigm used in the modern development of new drugs consists in the association of a disease with the functioning of certain proteins, so they must be blocked to cure diseases. Blockage is performed with the use of molecules that selectively bind to these proteins in an organism (inhibitors). The time and material expenditures at the stage of searching for inhibitors can considerably be reduced with the use of computer-aided molecular modeling methods. The precision of estimating the protein-inhibitor binding energy governs the efficiency of predicting the activity of an inhibitor. The effect of a solvent on the protein-inhibitor binding energy is predominantly determined via the free solvation energy. To calculate the free solvation energy, it is necessary to construct a solvent model. Implicit (often called continual) solvent models, in which a solvent is treated as a continuum (continual, continuous) medium with specified properties, including dielectric permittivity, are used more frequently. We consider in the book these continuum solution models.