Scientists are very afraid of being proven wrong.

But what really excited me was the idea that humans had a tremendous pre-history that went back millions of years. I wanted to go to Africa to find some of these creatures.

I think that many of my ideas are correct, but I'll bet you, before my death other discoveries will be made that will prompt me to alter various ideas I have about human evolution.

Lucy brought with her an image of our human ancestors that you don't get when you find a jaw or an arm bone or a leg bone. Here was 40 percent of a single skeleton.

In our case, finding a Lucy is unique. No one will ever find another Lucy. You can't order one from a biological supply house. It's a unique discovery, a unique specimen.

There have been some friendships lost over this. That's the most difficult for me. I find it very uncomfortable to know that I was at one time close friends with someone, and because of jealousies and misunderstandings and so on, these friendships have dissolved.

One has to devote oneself to a particular pursuit. To be successful at anything, you have to make a total commitment to it.