Clinical reasoning is a quintessential skill of the internist, the cornerstone of safe, effective medical care. While new technologies and accumulating evidence continue to change practice, they supplement rather than supplant clinical judgment in the care of the individual patient. Multiple studies show that transparency and instruction in clinical reasoning are what trainees seek most from their attending physicians. And while we know good reasoning when we see it, we often have difficulty describing it in specific terms.

With this issue, JGIM introduces readers to the lexicon of clinical reasoning with a new feature called Exercises in Clinical Reasoning. These exercises build on the successful format of other series that intersperse iterative case presentations with extemporaneous expert clinician commentary. We allow the reader to follow along as an experienced clinician approaches an unknown, challenging patient care dilemma. But we add another layer of commentary that peers into the clinician’s mind (as much as we can) to highlight the normal, insightful, and sometimes errant judgment displayed in attempting to solve each case. We hope that this running diagnostic reasoning commentary and concluding discussion will help our readers become more facile with the science of clinical reasoning, enabling them to become more cognizant of their own judgments and more effectively teach reasoning skills to others.

In this issue, “Doing What Comes Naturally” begins the Exercises with a relatively straightforward case involving a common clinical problem (hypertension) to introduce basic clinical reasoning concepts. In upcoming issues we hope to present cases with more twists, turns, blind alleys, or errors that highlight the more nuanced aspects of clinical reasoning. We invite clinicians to submit their interesting cases and to provide any suggestions or critiques on this new series.