The following is a script from "Bill Gates 2.0" which aired on May 12, 2013. Charlie Rose is the correspondent. Denise Schrier Cetta, producer. Matt Danowski, editor.
You probably know Bill Gates as the founder of Microsoft, the hard-driving tech executive whose software fueled the personal computer revolution.
You might also know him as the longtime richest man in the world who left Microsoft five years ago so he could work fulltime, giving his money away. We had the chance to witness "Bill Gates 2.0" -- the man you don't know. He is driven, as much as anyone we have ever met, to make the world a better place.
Gates told us why he thinks inventions are the key to success, and just what he intends to accomplish with his time, intellect and $67 billion fortune, starting with his plans to knock out some of the world's deadliest diseases.
Charlie Rose: You're going to spend the next 20 years of your life trying to eradicate disease, yes?
Bill Gates: Yep.
Charlie Rose: That's your mission?
Bill Gates: That'll be the majority of my time.
Charlie Rose: Starting with polio?
Bill Gates: Get it done by 2018.
Charlie Rose: Tuberculosis?
Bill Gates: That one we'll have to see how the tools go. The current tools are not good enough. We can - to do an eradication. They're good enough to reduce the - the deaths very dramatically. But we'll, we'll we need a few better tools that'll take probably six or seven years.
Charlie Rose: Malaria?
Bill Gates: Malaria's the one that the tools are being invented now. Fifteen and perhaps even 20 years. But start to really shrink that map.
These are the people Gates wants to help. They are what he calls "the bottom two billion" - a third of the world's population that struggles on less than two dollars a day. They are poor, hungry, lack electricity and clean water.
Gates' most urgent goal: help the millions of children under five who die every year, one every 20 seconds from preventable diseases.
Charlie Rose: No one alive that I know of has said, "My goal is to eradicate a disease and then another disease and then another disease." This is somebody that dreams high.
Bill Gates: Yeah, because I'm excited about that. And it's doable.
Today, Gates spends most of his time here, at the Bill and Melinda Gates Foundation in Seattle. He runs it with his father, Bill Sr., and his wife, Melinda, whom he credits with being a driving force behind the foundation.
There are over 1,100 employees to help them decide which programs to fund, but Gates still visits sites around the world to see what's working and what's not.
[Girl: I welcome Bill Gates to our school. The government of Ghana and all school age children are grateful for your support.
Bill Gates: Very well done. Great to be here.]
The grants here go towards school nutrition, improving agriculture and, most important to Gates, life-saving vaccines.
Bill Gates: Well, whenever you see a mother bringing a sick child into a facility, it's easy to relate to, "What if that was my child?" You realize, how crazy it is that with the world being rich enough to afford all sorts of frivolous things, that those basic things still aren't being provided.