There Are Many Good Epidemiology Textbooks On The Market, But Most Of These Are Addressed To Students Of Public Health Or People Who Do Clinical Research With Epidemiologic Methods. There Is A Need For A Short Introduction On How Epidemiologic Methods Are Used In Public Health, Genetic And Clinical Epidemiology, Because Health Professionals Need To Know Basic Epidemiologic Methods Covering Etiologic As Well As Prognostic Factors Of Diseases. They Need To Know More About Methodology Than Introductory Texts On Public Health Have To Offer.