| Abstract: | An introduction to the Lifshitz theory of the dispersion forces that includes as limit cases the van der Waals and Casimir forces is provided. A critical role of the fluctuation-dissipation theorem is stressed in the origin of the force between neutral bodies without permanent dipole moment. Special attention is paid to the thermal correction to the force. Its physical nature is explained. It is demonstrated that modern experiments, measuring the dispersion forces, do not support the Lifshitz theory and the reason for the disagreement is still not clear after 25 years of intensive research. A critical experiment currently running is proposed that can shade light on the basis of the problem. |