Taking a unique approach to case studies research -- specifically that case studies are a useful tool for hypothesis testing on social phenomena -- Yin introduces the research professional or graduate student to the case study method. He shows the reader how to use the case study method as a research strategy and demonstrates its utility through short vignettes that illustrate important techniques. The revised edition of this landmark volume includes a description of the role of theory in designing case studies and generalizing from the results, as well as a new discussion of the method for determining the number of case studies to use in a multiple-case study.