It was my first day on the ground in India. The year was 1992 and I had graduated from college a few months before. I was working as a research assistant at the World Bank and this was my first chance to leave the air-conditioned Washington, D.C., headquarters and see what development work actually was like in the field.

I remember the heat hitting me as my colleague Dr. Salim Habayeb and I walked out of the airport. We headed toward our cab and before we made it to the door, a small boy came up to us, grabbed my leg, lifted up his shirt to show the burn marks covering his chest, and then held out his hand to beg for money. After freezing for a minute in shock, I started to reach for my purse. Salim, who had worked in public health for many years, kindly put his hand over mine and said a firm “no.” He explained that someone had likely burned this boy to enable him to beg more effectively, and if I gave him money, they would do it again. We got into the cab and drove away, tears pouring down my face.

Over the next few weeks as Salim and our colleague Maria Donoso Clark and I traveled throughout India working on a program to treat leprosy, I had many such learning moments. I met patients who had been cast out of their homes and families due to their disease. I saw acts of despair, acts of kindness, and acts of greatness—all in an environment that nothing in my childhood in Miami could have prepared me for. Most importantly, I saw how dedicated people could make a real difference.

During the days, I worked harder than I ever had in my life trying to do my small part to help. At night, I cried myself to sleep.

In the decades since my first trip to India, a lot has improved, even though the gap between rich and poor has increased dramatically and deep poverty remains. India’s economy has developed. Leprosy has gone from afflicting more than 3 million people to fewer than 100,000. Each time I visit I am amazed at the vibrancy of the Indian people and economy and the improvements to health they have achieved.

I was last in India three years ago. I was there not as a 22-year-old in her first job but on an official visit as the chief operating officer of Facebook. More importantly, I was visiting as a mother—on this trip, Craig Kielburger and my nine-year-old son and six-year-old daughter were with me. I want my children to grow up understanding what I did not learn until I was 22—that the luck of birth determines so much of our lives and that those of us with opportunity also have responsibility. And I want my children to see how even when problems might seem overwhelmingly large, individuals can make a difference.

Our time with Craig in Rajasthan showed all of this so clearly. We visited a one-room village school and helped build a wall for a new school that will provide multiple classrooms so more children will

have the opportunity to learn. We helped families who had relied on polluted water sources carry clean water from their new community well to their homes. We attended a Lean In Circle meeting with women

who are participating in a financial literacy program that has helped them save money and send their daughters to school for the first time. All of this is happening because WE Charity, a program started by Craig when he was just 12 years old, is working in these communities—and making a huge difference.

This book is about how we can all work to improve the lives of others. The problems in the world can seem overwhelming—5.9 million children under the age of five die each year of preventable or curable diseases,more than 700 million people still lack access to clean water, and 46 million people live in slavery. But even a single person can make a huge difference, as each of the authors of this book shows us every day. There are no simple solutions, but there are solutions that can

be created and deployed. Companies, nonprofits, governments, and hybrid social enterprises each have their own role to play—and the authors of this book have been leaders in all these realms. As Holly Branson, Marc Kielburger, and Craig Kielburger share their stories and insights in these pages, the interwoven nature of the “WEconomy” is brought to light for all of us. As you start out on your own journey, ask yourself: What kind of world do you want to live in? Dream big—dream of a world that is just and fair, where all have equal opportunity to live healthy, happy, and productive lives. How much will you do to create that better world? Whatever your path may be—in business, in

government, in a nonprofit—how will you contribute to the lives of others? What legacy will you leave for your children and for all children?

At Facebook, we have posters on the walls that inspire us, such as Fortune Favors the Bold or Done Is Better Than Perfect. I have two favorites: Nothing at Facebook Is Someone Else’s Problem and What Would You Do If You Weren’t Afraid? What would you do if you believed that all of the problems out there could be solved and that it was your responsibility to solve them? What would you do if you weren’t afraid?

Please ask yourself those questions and decide what you’d do. And then go do it.