Debugging concurrent systems is notoriously hard, since bugs may manifest only for some interleavings among the processes’ execution, and since debugging them may involve analyzing multiple processes. We claim that two key ingredients for such an analysis are reversible execution, to explore a faulty computation back and forward, and causal analysis, to identify the causes of a visible misbehavior. In this talk we focus in particular on the use of reversible execution, as enabled by CauDEr, a reversible debugger for concurrent Erlang programs.