Abstract
Using literature on materials science, one often encounters the notion of the Hubbard model HM. Although frequently used in calculations, the HM still remains somewhat mysterious. The aim of this paper is to present a mini-review of the HM for the nonspecialized readers. The HM has become a complex research subject. Therefore, this paper will be limited to those aspects of the model with which the author has had research contact. The first section is devoted to the basics of the HM. The following part is devoted to thermodynamics and electrical conductivity. Reflectivity of the HM is then defined and briefly discussed. Examples of results concerning conductivity and reflectivity are treated next. The paper ends with a few comments.