The dream that AJ embodies, the perfection of memory, has been with us since at least the fifth century B.C. and the supposed invention of a technique known as the "art of memory" by the Greek poet Simonides of Ceos.

Simonides had been the sole survivor of a catastrophic roof collapse at a banquet hall in Thessaly. According to Cicero, who wrote an account of the incident four centuries later, the bodies were mangled beyond recognition. But in his mind, Simonides was able to close his eyes to the chaos and see each of the guests at his seat around the table. He'd discovered the powerful technique known as the loci method. If you can convert whatever it is you're trying to remember into vivid mental images and then arrange them in some sort of imagined architectural space, known as a memory palace, memories can be made virtually indelible.

Peter of Ravenna, a noted Italian jurist and author of a renowned memory textbook of the 15th century, was said to have used the loci method to memorize the Bible, the entire legal canon, 200 of Cicero's speeches, and 1,000 verses of Ovid. For leisure, he would reread books cached away in his memory palaces. "When I left my country to visit as a pilgrim the cities of Italy, I can truly say I carry everything I own with me," he wrote.

It's hard for us to imagine what it must have been like to live in a culture before the advent of printed books or before you could carry around a ballpoint pen and paper to jot notes. "In a world of few books, and those mostly in communal libraries, one's education had to be remembered, for one could never depend on having continuing access to specific material," writes Mary Carruthers, author of The Book of Memory, a study of the role of memory techniques in medieval culture. "Ancient and medieval people reserved their awe for memory. Their greatest geniuses they describe as people of superior memories." Thirteenth-century theologian Thomas Aquinas, for example, was celebrated for composing his Summa Theologica entirely in his head and dictating it from memory with no more than a few notes. The Roman philosopher Seneca the Elder could repeat 2,000 names in the order they'd been given to him. A Roman named Simplicius could recite Virgil by heart—backward. A strong memory was seen as the greatest of virtues since it represented the internalization of a universe of external knowledge. Indeed, a common theme in the lives of the saints was that they had extraordinary memories.

After Simonides' discovery, the art of memory was codified with an extensive set of rules and instructions by the likes of Cicero and Quintilian and in countless medieval memory treatises. Students were taught not only what to remember but also techniques for how to remember it. In fact, there are long traditions of memory training in many cultures. The Jewish Talmud, embedded with mnemonics—techniques for preserving memories—was passed down orally for centuries. Koranic memorization is still considered a supreme achievement among devout Muslims. Traditional West African griots and South Slavic bards recount colossal epics entirely from memory.