Catheter ablation of atrial fibrillation (AF) has evolved dramatically over the last several years. The initial efforts in the catheter-based management of AF targeted the atrial substrate in an effort to mimic the maze procedure. After the pulmonary veins (PV) were shown to be critical in the initiation and perpetuation of AF, the focus then shifted to a trigger approach in which the PVs and other foci were targeted for ablation. The pendulum then appeared to swing back toward the substrate approach after it was shown that left atrial circumferential ablation afforded improved outcomes in patients with paroxysmal and persistent AF. It has become clear that there are several possible approaches in the catheter ablation of AF, each with its strengths and limitations. It is also becoming evident that not all patients will respond to a single ablation technique and that the ablation protocol is best tailored to suit the individual patient. This article strives to present an evidence-based review of the many techniques, and then offer a practical guide to the catheter ablation of AF.