Cardiac resynchronization therapy (CRT) is an accepted treatment for patients with heart failure (HF), impaired left ventricular (LV) function, and a wide QRS complex. It has been revolutionary for patients with advanced HF whose only previous option was cardiac transplantation, and it is now a realistic option for patients with mild HF. The development of CRT also has united the previously disparate cardiological subspecialties of electrophysiology and HF. This review, written on the occasion of the 20th anniversary of the first clinical use of CRT for HF, takes a historical perspective on CRT's evolution from "bench to bedside." We also comment on the task faced by electrophysiologists and HF specialists as they make this life-saving therapy available to an increasing number of eligible patients.