Our family has begun to deploy as much as 99 percent of our fortune to bring prosperity to Central America, home to some of the poorest people in the Western Hemisphere.

For 20 years, beginning in 1980 in Boston, I tried my luck as a computer software entrepreneur. There were ups and downs, mostly downs. Then, when Cisco Systems bought my telecom startup in 1998, I suddenly found myself $10 million ahead.

I had no practice being rich and didn't really know what to do with the money. When my wife proposed that we use our new fortune to help other people, it sounded just right.

Elementary business analysis principles kicked in right away. Where would I get the biggest bang for the buck? Clearly, each dollar can do more to help poor people than to help rich people. And one can always get better returns doing the things one does best in the field one knows best. Thirty years earlier, I had been a mathematics teacher in Honduras and I had also taught English to Central American war refugees in Boston. Central America was the place where I knew best how to make a difference.

Central Americans living on a dollar or two per day need everything. They need food, teachers, roads, medicine and better government. Most traditional aid has left them as poor as ever. So what commodity is most needed, most durable and can travel cheaply over a hundred miles of bad roads? My answer was information. And my chosen vehicle was rural libraries and Internet centers.

So we launched the Riecken Foundation. Its first community library was dedicated two years later in the remote mountain village of Sulaco, Honduras.

Most public libraries die young in Central America. They fall into disuse through neglect, lack of funding, absentee management, and the failure to include local residents in their management. Our goal went beyond erecting library buildings; it was to breathe life into palaces of discovery with windows on the world that would open wider every year.

Our libraries are noisy and cheerful, filled with children and adults who explore the open book stacks, do research on the Internet, and form community service groups. They are among the most respected institutions in their communities.

Riecken libraries have sparked dramatic changes in village culture. Youth in Riecken communities spend more time in study and less time watching television. Library access leads teachers to assign research projects instead of memorization of textbook pages. Popular youth service groups undertake initiatives in journalism, theater, environmental protection, and computer skills, preparing the next generation of national leaders. Trustees trained in honest library accounting come to demand the same openness from their mayor's office.

As our resources have multiplied, so has the scale of our ambitions for Central America, and we have expanded from cultural work to communications and advocacy. Those efforts are funded through my merchant bank; Paperboy Ventures.

When I learned in 1998 that Amylin Pharmaceuticals, then a tiny biotech developing an important diabetes medication, was facing imminent financial extinction, I decided to put most of my assets into saving its new medicine. If the medicine didn't work, we would still have enough left for our daughters' education and a modest retirement; if it did work, we might enhance the health of millions. Our investment, joined by others, brought two important new diabetes therapies to market, directed Amylin toward a multibillion value, and vastly multiplied my own resources.

In 2003 that enhanced fortune turned into Paperboy Ventures, which was founded to support under-appreciated new scientific discoveries. We have nurtured biofuels production, linguistic analysis for Internet search, therapies for lupus and depression, and new materials for arterial surgery.

All of Paperboy's gains are destined for my work in Central America and the Paperboy staff likes to say that it is the for-profit arm of a non-profit venture. Paperboy profits have provided support for our newspaper, El Patriota, which provides an independent voice in Honduras. The Democracy Without Borders Foundation advocates effectively for open legislative processes, open telecommunications access, and impartial enforcement of forest protection laws. In Honduras in 2004, we organized a 100-mile march to give voice to thousands of citizens demanding an end to deforestation. Three years later in El Salvador, we organized a march of 25,000 people demanding potable water in poor neighborhoods.

We want the best international standards in business and government – including honest bookkeeping, universal Internet access, quality manufacturing, streamlined trade and transparent regulation – to become standard practice in Central America.

The keys to success in deploying social wealth are the same as the keys to success in amassing private wealth: personal effort and unrelenting focus on results. These are the best years of my life. Unlocking Central America's potential is more complex, more challenging, and more satisfying than any problem I have faced as an engineer or businessman.

As a serial entrepreneur, I remember the thrill every time I opened a tiny new laboratory in the industrial slums behind M.I.T. No matter how humble the beginning, each new beginning carried a promise of greatness. Now as a social entrepreneur, when I go to a library inauguration where the whole town turns out and dozens of children burst through the doors for books, to use the computers, or to find a place at a chessboard, I feel that thrill all over again.

Manage your social contributions actively, and you will increase the effect by at least a factor of 10. I would urge anyone who wants to do something important in the world to go all the way. Give it every hour you can spare as well as every dollar. The things that most need doing in the world are also the hardest, and that means they will always require more effort than money.

Successful entrepreneurs typically earn great fortunes because they like to work hard, accomplish their goals, and win against the odds. We should deploy those same personal drives to maximize our social impact and, incidentally, our own happiness.