...who we are and what we do it is fundamentally a function of what we remember.

All across Africa, the Pacific and the Americas, we find cultures that didn't know about mouth kissing until their first contact with European explorers. And the attraction was not always immediately apparent. Most considered the act of exchanging saliva revolting.

If you want to live a memorable life, you have to be the kind of person who remembers to remember.

Our lives are structured by our memories of events. Event X happened just before the big Paris vacation. I was doing Y in the first summer after I learned to drive. Z happened the weekend after I landed my first job. We remember events by positioning them in time relative to other events.

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.

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.

When we first hear [a] word, we start putting these associational hooks into it that make it easier to fish it back out at some later date.