So far as 'General Bacteriology' is concerned, the fundamental subject has been properly arranged with special reference to the chapters on Antibiotics and Chemotherapeutics, Immunology (and hypersensitivities) with some special amplification of Molecular Biology, Genetics, Immunogenetics. In the case of 'Systematic Bacteriology', there has been thorough change with the incorporation of certain new genre, and latest investigations of their kinds. However, referentially, the readers should focus attention to the chapters interobacteriaceae I and II and 'Miscellaneous Bacteria' chapter. In the Virology chapter, the latest scientific classification and taxonomical positions have been elucidated.