The ability to compute the forces operating among various atoms with the help of Lifson’s method has facilitated a basic clarification of the structure and dynamics of biological molecules and eventually led to a breakthrough in understanding protein folding and diseases caused by defective folding. Today, numerous studies of protein folding are designed on the basis of predictions obtained through such computations. The consistent force field method also enables the precise planning of chemical reactions and the study of the function of various molecules in biological systems, among them the interactions between different proteins, the binding of ions to biomolecules, and the redesign of proteins.