This article examines the arguments of two of the most influential books addressing research design strategies for making causal inferences in social science: G.King, R.Keohane and S. Verba’s Designing Social Inquiry (1994) and H.Brady and D.Collier’s Rethinking Social Inquiry (2004).The author offers her own set of basic rules that should guide all social science inquiry, the aim of which is causal inference. These rules apply not only to scholarship that falls in either the quantitative or qualitative category, but also to that which makes use of both sets of tools. The author also suggests a set of organizing principles for social papers concerned with causal inference.