A large number of high-quality figures, which represent the core of the authors’ work, enrich the contents: all cases are built around suggestive figures acquired during the patients’ hospitalization, which clearly illustrate important concepts used in catheter ablation of cardiac arrhythmias. The figures are not only related to the catheter ablation procedure, but also to the patient history, thus helping the reader to place the invasive treatment of the arrhythmias into clinical context: electrocardiograms, Holter ECGs, signal-averaged ECGs, chest X-Rays, transthoracic and transesophageal echocardiography images, MRI, CT scans, coronary angiography images are provided when considered relevant, in order to better present the patient’s condition. Short videoclips with activation maps of the atria or the ventricles during the studied arrhythmia complete the information provided.