 The Common Cause Principle (RCCP) was introduced by Hans Reichenbach, in The Direction of Time, which was published posthumously in 1956. The principle posits a connection between causal structure and probabilistic correlations between events. After presenting the principle in  Section 2,  we will provide some historical background in  Section 3.  The following two sections present some illustrations and alleged counterexamples to RCCP.  Section 6  discusses Reichenbach’s fork asymmetry, a (putative) temporal asymmetry in macrostatistical patterns that he associated with RCCP.  Section 7  presents the Causal Markov Condition, which plays a central role in causal modeling methods. The Causal Markov Condition is often seen as a modern successor of RCCP, and its relationship to RCCP will be examined.  Section 8  will develop RCCP in a formal setting that is suitable for examining the status of RCCP in quantum mechanics.  Section 9  and  Section 10  will then consider whether RCCP is compatible with quantum physics.