This book provides a detailed examination of what is required for a body of knowledge to be considered scientific. Cohen treats general topics like value bias, the nature of observation, and the limitations of the scientific study, but he also discusses specific topics like the elements of a theory and the necessity of restricting the scope of knowledge claims. The second edition contains substantial new material including new chapters dealing with the problems of quantitative measurement, research design, the limits of empirical research, and the methodology of cumulative research programs.