Process tracing is a key method in qualitative analysis, often underutilized and misapplied. This article introduces a new framework for process tracing, emphasizing causal sequence, description, and causal-process observations (CPOs). It highlights the method's ability to contribute to both descriptive and causal inference, particularly in political and social contexts. The article includes online teaching exercises across various fields, including American politics, comparative politics, international relations, and public health. Process tracing involves identifying diagnostic evidence to support causal claims, relying on prior knowledge and empirical regularities. It can complement quantitative methods by providing inferential leverage, especially in small-N designs. The article discusses four causal inference tests: straw-in-the-wind, hoop, smoking-gun, and doubly decisive. These tests help evaluate hypotheses, with the latter two offering strong inferential support. The article also illustrates these concepts using the Sherlock Holmes story "Silver Blaze," showing how process tracing can uncover causal mechanisms. The method is valuable for both qualitative and quantitative research, though challenges remain in its application and teaching. The discussion underscores the importance of careful description and the integration of qualitative and quantitative methods to enhance causal inference.Process tracing is a key method in qualitative analysis, often underutilized and misapplied. This article introduces a new framework for process tracing, emphasizing causal sequence, description, and causal-process observations (CPOs). It highlights the method's ability to contribute to both descriptive and causal inference, particularly in political and social contexts. The article includes online teaching exercises across various fields, including American politics, comparative politics, international relations, and public health. Process tracing involves identifying diagnostic evidence to support causal claims, relying on prior knowledge and empirical regularities. It can complement quantitative methods by providing inferential leverage, especially in small-N designs. The article discusses four causal inference tests: straw-in-the-wind, hoop, smoking-gun, and doubly decisive. These tests help evaluate hypotheses, with the latter two offering strong inferential support. The article also illustrates these concepts using the Sherlock Holmes story "Silver Blaze," showing how process tracing can uncover causal mechanisms. The method is valuable for both qualitative and quantitative research, though challenges remain in its application and teaching. The discussion underscores the importance of careful description and the integration of qualitative and quantitative methods to enhance causal inference.