Fifty years ago this Sunday, the first adult human heart transplant was performed in Cape Town. It was an epoch-making advance in science — and also, perhaps, in human culture. The heart, heavy as it is with symbolism, has always occupied a special place in our collective imagination. Despite our relatively sophisticated biomedical understanding of its function, many people still think of the heart as the seat of affection and courage. When Barney Clark, a retired dentist with end-stage heart failure, received the world’s first permanent mechanical heart in 1982, his wife worried he might not still be able to love her.

A heart transplant is the definitive treatment for the most severe stages of heart failure, a disease that afflicts six million Americans (and a quarter of a million in its most advanced form). But as recently as the early 1960s, transplanting a human heart seemed like a pipe dream. Organ rejection and life-threatening infections posed prohibitive risks. By the second half of the decade, however, animal research had pointed a path toward human transplantation.

In the end, the race to transplant a human heart — a story engagingly told in Donald McRae’s 2006 book, “Every Second Counts” — involved four surgeons, the most compelling of whom were Christiaan Barnard at Groote Schuur Hospital in Cape Town and Norman Shumway at Stanford. The two had been surgical residents together at the University of Minnesota, and by many accounts they had a frosty relationship. Dr. Shumway scorned what he saw as Dr. Barnard’s showmanship, aggressiveness and willingness to cut corners. Dr. Barnard, for his part, was resentful that his colleague seemed to view him primarily as a foreigner from a pariah country.