The essence of the heartbeat remained a mystery for centuries. William Harvey, in his description of the circulation of blood, did not explain the origin of the heartbeat. He stated that “the pulse has its origin in the blood…the cardiac auricle from which the pulsation starts, is excited by the blood.” It was held for several centuries that the heartbeat was triggered by inherent excitation of the heart muscle itself (myogenic theory) or was due to an electrical stimulus from the nervous system (neurogenic theory). This chapter discusses the ultimate discovery of the origin of the heartbeat and the conducting system by anatomists and pathophysiologists: Jan Evangelista Purkyně, Wilhelm His, Jr. Walter Gaskell, Sunao Tawara, and Arthur Keith. It also discusses the current concepts of impulse generation and its transmission in the human heart.