Build a Billion-Dollar Business It starts with strategic thinking and thoughtful growth. Here's an inside look at how two successful businesses went from zero to $1 billion.

As an entrepreneur, you've probably set your sights high. You dream of a reality that others would brush off as, well, simply a dream. You envision creating a brand that crosses oceans and continents in its importance and recognition. You don't think in multiples of one, but instead in hundreds, perhaps thousands. And you might even be calculating not if but when your business will officially cross the threshold from the millions to $1 billion. And even in the throes of a recession, you hold on to that vision, knowing that if you can build the foundation and survive now, you will thrive later.

We recently caught up with two individuals who have survived turbulent waters, skillfully navigating their companies through the dotcom bust and building billion-dollar companies before age 40. Here's how they made a billion happen--in their own ways and on their own terms.