Over the past decades, interest in atrial fibrillation (AF) has greatly increased, and the understanding of its pathophysiology and potential treatment modalities is constantly growing. This article summarizes findings that the authors deem milestones in the clinical management of the arrhythmia. The first milestone was the observation that AF is not a benign entity; rather, it is associated with an increased risk of death and morbidity. While no trial had previously shown that patients live longer if AF is suppressed, the epidemiological association is very consistent among several populations. The second milestone was the discovery that thromboembolic strokes can be prevented by warfarin or (to a lesser extent) antithrombotic therapy. The third milestone was the finding that-with contemporary treatment-rhythm control did not improve patient outcomes and, in fact, that with regard to mortality, rate- and rhythm-control strategies are largely interchangeable. Fourth, the description of a specific trigger of the arrhythmia localized in the pulmonary veins has driven efforts to curatively treat AF. While no survival benefit has so far been shown for patients treated with catheter ablation, this technique has progressed from an innovative investigational procedure to routine clinical practice. The fifth milestone is the addition of outcome data to the current body of evidence. In the ATHENA trial, for the first time, an antiarrhythmic agent proved to reduce cardiovascular mortality and morbidity. In summary, the development of novel treatment strategies for AF is highly dynamic and productive. Years to come will likely witness significant changes in perspective and prognosis of affected patients.