Ventricular tachyarrhythmia is an important cause of morbidity and sudden death. Although implantable cardioverter-defibrillator (ICD) reduces the risk of arrhythmic death, ICD therapies are associated with an increased mortality and worsening quality of life. Antiarrhythmic drugs may be effective in preventing arrhythmia recurrences but have an increased adverse effects and non-cardiac mortality. Catheter ablation has evolved into an effective intervention in patients with and without structural heart disease. This monograph is a collection of thought-provoking challenging case scenarios. These cases emphasize important electrocardiographic and anatomic features, illustrating crucial diagnostic maneuvers, mapping techniques, imaging integration, as well as formulating the ablation strategies.