An energetic young man by the name of Ankur Jain blew into the Inc. offices a couple of months ago to sell me on the idea of getting involved with the Kairos Society, an organization he launched three years ago. Its focus, he told me, "is to bring together the world's top collegiate entrepreneurs to create the next billion-dollar, high-growth, job-creating ventures to solve some of the world's greatest problems." Jain is all of 21, a senior at the University of Pennsylvania, the son of a muckety-muck with contacts to spare, and, like a lot of entrepreneurs, a whirlwind of ambition, salesmanship, and enthusiasm. He invited me to participate in his spring conference, on a panel of experts and students discussing entrepreneurial ways to bring clean water to those who need it most.

I accepted, and I met a lot of great people, including John Oldfield of the WASH Advocacy Initiative, Kurt Soderlund of the Safe Water Network, and Frank Rijsberman of the Gates Foundation. I also talked to some really impressive students, who flew in from all over the globe. Particularly engaging were the students from Brown and the Rhode Island School of Design who, through their enterprise WaterWalla, are planning to attack the problem of purifying drinking water in distressed neighborhoods in urban India. At one point, I asked them how they were going to organize their venture. For-profit? Nonprofit? Though they hadn't yet decided, they assumed it would be a nonprofit.

There was a time when that would have been the right and only answer. Now, however, there are a slew of business models that accommodate the ambitions of mission-driven entrepreneurs. Suzi Sosa,'s social responsibility blogger, explained it to me recently: The business model that fits best depends on your goal, your customers, the ease or difficulty of putting together money, the tax consequences, and the like. For every enterprise, there is a preferred model.

This month, we've put together a feature package that looks at the various ways socially conscious companies can be organized for maximum success. We begin with the story of Cascade Engineering, a Michigan manufacturing company that has recently been certified as the largest B Corporation in the nation. Its founder and CEO, Fred Keller, is a nice counterpoint to the stereotype that socially responsible entrepreneurs are all young, idealistic, and steeped in liberal politics. Keller is middle-aged, clear-sighted, and Republican. Then we introduce some newer, smaller companies and explain why they've chosen their particular business models. As we were putting this issue together, I thought often of the WaterWalla kids and all the other bright college students I met at the Kairos Society summit. I hope they will find our feature package useful and informative. I hope it will give them practical insight into all the new, creative approaches to the age-old business of saving the world. And I hope they succeed.

Jane Berentson