The textbook takes into account new data on the classification of microbes, the decisions of the 7th International Congress on Taxonomy of Viruses on the entry into force of the new classification of viruses on January 1, 2002, as well as the list of microbes and diagnostic studies corresponding to Order of the Ministry of Health of the Russian Federation No. 64 of 21.02.00 "On Approval of the Nomenclature of Clinical Laboratory Studies." The textbook consists of 20 chapters, which consistently deal with issues of general and private microbiology, virology and immunology.