I’ve visited a lot of urban slums and it’s always difficult to describe to people back home just how bleak they can be. If you want to read an unvarnished, first-hand account of life in one of India’s slums you should pick up Behind the Beautiful Forevers: Life, Death, and Hope in a Mumbai Undercity.

The book was written by Katherine Boo, an award-winning Western journalist who spent three years getting to know the people of Annawadi, a slum of about 3,000 people on the edge of a sewage-filled lake in India’s largest city. Her research alone is a tremendous achievement.

The centerpiece of the story is a family falsely accused of a crime. Their story becomes a way to understand the very tough position people living in slums are in, and the great injustices that happen in a slum. It’s a reminder of how capricious their life can be.  In Annawadi, exploitation and corruption are rampant and you can’t count on fairness or even basic justice if you are one of the world’s poorest.

Ironically, Annawadi survives—for now—amidst gleaming luxury hotels that reflect Mumbai’s status as India’s richest city and its commercial and entertainment capital.

Most of the people come from other parts of India, hoping for a better life. It’s hard for us to imagine that life could be much worse somewhere else. But many poor people are leaving the rural regions on their own because there is at least relative freedom in the slums and also the possibility that you could find something new to do.

Many people in Annawadi survive by scavenging garbage and some by thievery because that’s the only way they can see to make money. Sickness and disease are always present. And life is often unpredictable. Like many slums, the people don’t own the land, so they never know when the government is going to come in and push them out.

So it’s a sad story and it makes you want to help. It reminds us how much more work needs to be done to address the inequities in the world. But it’s also uplifting at times because Boo shows people striving to make a life for themselves, sacrificing for their families, and in their own way, being innovative and entrepreneurial in creating a vibrant local economy.

More broadly, the story of Annawadi reflects the big and growing problem of urban slums. More than 900 million people live in poor, densely-populated areas in developing countries. Over the next several decades, that number is expected to increase to several billion.

Many urban centers are ill-prepared to meet the basic needs of rapidly expanding urban populations today, so it’s sobering to think about it getting worse. It’s difficult for donor organizations and governments to help because there are so many complex local systems involved, such as water, sanitation, policing, the judiciary, and education.

And as Boo shows, even aid organizations can be corrupt, although I do think the two examples she cites can be misleading. I know from first-hand experience that there are thousands of fantastic NGOs and government organizations—in India and elsewhere—working hard and honestly to improve living conditions for the poor.

The foundation works with many of them, including some that are focused specifically on addressing urban poverty. We’re investing in better sanitation and financial services for the poor, which can make a difference in places like Annawadi. We have made improving health a top priority because we believe it is the basic building block for people to make the most of their lives. This includes investing in vaccines and other drugs to tackle diseases that disproportionately affect the poor, and working to improve health care for mothers and children.

All of these things will make an impact in urban slums. But there’s no doubt that urban poverty is a uniquely complex and vexing problem—without a quick or simple solution. As the world population grows by another 2 billion over the next several decades, most of that increase will show up in urban slums. The challenge for our foundation and for other donors is to find ways to collaborate with governments so that aid programs work in tandem with effective delivery of basic services. Otherwise, the suffering and often brutal nature of life will continue for the world’s urban poor. On my trip to India this week, I visited an urban slum in Lucknow, the capital city of the state of Uttar Pradesh, to see what’s working and continue to look for ways we can help improve the lives of the poorest.

After reading the book I had a few questions I wanted to ask Katherine Boo. She has agreed to write a response to my questions which we’ll post here on Gates Notes soon.