Robert Langer: I was 11 years old. I had this Gilbert chemistry set.  I have always liked magic.  This maybe sounds silly, but I always liked magic, and chemistry is always very magical.  I mean, the kinds of things, like I remember, when I was a little boy, you have these solutions and you could take one solution and mix it with another, and all of a sudden it would change to a third color.  You could mix one thing with another and it would turn into rubber, and those are reactions. I thought, “Boy, this is really neat!” I guess I was just always fascinated with that.  So I think maybe just the visualization — even when I didn’t understand things that well — I thought it was fun and exciting.  And then I guess when I actually took chemistry, there was something — I don’t want to say magical — about it, but something that I enjoyed solving the problems, the chemistry problems, and I enjoyed reading about some of the things. Not all of the things.  I was excited about what it could do.