Defibrillation is one of the most successful and widely recognized applications of electrotherapy. It is the only available treatment of sudden cardiac death due to ventricular fibrillation. It is also one of the most well known triumphs of biomedical engineering. Yet the historical road to its first successful application in a patient and the innovative adaptation to an implantable device are marred with unexpected turns, political and personal setbacks, and public and scientific condemnation at each new idea. Driven by dedicated scientists and ever-advancing creative applications of new technologies, from electrocardiography to high density mapping and computational simulations, the field of defibrillation persevered and continued to evolve to the life-saving tool it is today. In addition to critical technological advances, the history of defibrillation is also marked by the plasticity of the theory of defibrillation. The advancing theories of success have propelled the campaign for reducing the defibrillation energy requirement, instilling hope in the development of a painless and harmless electrical defibrillation strategy.