This book discusses all aspects infectious CNS pathology, including different bacterial, viral, fungal, mycoplasma and protozoan pathogens, accompanied by illustrations that show macro- and histopathological changes. It also presents microbiological, epidemiological and clinical data, with a particular focus on meningitis and encephalitis of different bacterial and viral aetiologies, influenza, COVID-19 and other viral and bacterial generalized infections. Further, the book explores the importance of mixed infections, including those in the late stages of HIV infection, as well as pathological changes in different age groups including newborns. A special chapter is devoted to the probable role of biological pathogens in noninfectious brain pathology.