From reviews of the first editon: "A much-needed, descriptive, informative, comprehensive, and up-to-date guide to the many theoretical facts as well as the important practical applications of observational epidemiology. [The authors] expand on many concepts their colleagues merely label and focus these topics as the essence of epidemiological issues.... The book is excellently illustrated with appropriate tables and figures that aid in the lucid presentation and clarification of the concepts and examples covered.... Should serve as an excellent text for students learning methodology in epidemiology and as a handy and reliable reference source for scientists and researchers actively involved in non-experimental epidemiologic investigations." --The Yale Journal of Biology and Medicine