During the Middle Ages they understood that words accompanied by imagery are much more memorable. By making the margins of a book colorful and beautiful, illuminations help make the text unforgettable. It's unfortunate that we've lost the art of illumination.

Growing up in the days when you still had to punch buttons to make a telephone call, I could recall the numbers of all my close friends and family. Today, I'm not sure if I know more than four phone numbers by heart. And that's probably more than most.

Memory training is not just for the sake of performing party tricks; it's about nurturing something profoundly and essentially human.

Once upon a time, this idea of having a trained, disciplined, cultivated memory was not nearly so alien as it would seem to us to be today.

With our blogs and tweets, digital cameras, and unlimited-gigabyte e-mail archives, participation in the online culture now means creating a trail of always present, ever searchable, unforgetting external memories that only grows as one ages.

What makes things memorable is that they are meaningful, significant, colorful.

Just as we accumulate memories of facts by integrating them into a network, we accumulate life experiences by integrating them into a web of other chronological memories. The denser the web, the denser the experience of time.