The world has been very careful to pick very few diseases for eradication, because it is very tough.

OK, I have a nickname. My family calls me 'Trey' because I'm William the third. My dad has the same name, which is always confusing because my dad is well known, and I'm also known.

I don't think I would have spent time learning about the immune system if understanding vaccines weren't something I considered very important.

The scientific understanding of some of these [childhood] diseases is advancing quite rapidly. There's some things like premature birth or nutrition, first day deaths that we need a lot more insights so that we can build the tools to solve those problems.

I'm sorry that we have to have a Washington presence. We thrived during our first 16 years without any of this. I never made a political visit to Washington and we had no people here. It wasn't on our radar screen. We were just making great software.

Success is a lousy teacher.

In my view, investing in public libraries is an investment in the nation's future.