Epidemiology is the study of the distribution of various diseases in the human population and the factors that shape this distribution. Epidemiological methods, in contrast to experimental methods, focus on human populations and, unlike traditional clinical research, epidemiological investigation involves groups and is usually comparative. The collective and comparative approach underlies the superiority of epidemiology over case-based clinical research, while the lack of mandatory nosological correspondence between humans and various experimental animals is a point of superiority of epidemiology over experimental research. 

This book contains the principles and methods of general epidemiology as well as its applications in etiological research, clinical medicine, and public health services.