To attain the rank of grand master of memory, you must be able to perform three seemingly superhuman feats. You have to memorize 1,000 digits in under an hour, the precise order of 10 shuffled decks of playing cards in the same amount of time, and one shuffled deck in less than two minutes. There are 36 grand masters of memory in the world.

We've outsourced our memories to digital devices, and the result is that we no longer trust our memories. We see every small forgotten thing as evidence that they're failing us.

I met with amnesiacs and savants, educators and scientists, to try to understand what memory is, why it works, why it sometimes doesn't, and what its potential might be.

Our ability to find humor in the world, to make connections between previously unconnected notions, to create new ideas, to share in a common culture: All these essentially human acts depend on memory.

Part of being creative is not being super-duper focused.

If you were a medieval scholar reading a book, you knew that there was a reasonable likelihood you'd never see that particular text again, and so a high premium was placed on remembering what you read. You couldn't just pull a book off the shelf to consult it for a quote or an idea.

The fact that books today are mostly a string of words makes it easier to forget the text. With the impact of the iPad and the future of the book being up for re-imagination, I wonder whether we'll rediscover the importance of making texts richer visually.