Sue, the CEO of our foundation, is a great partner for Melinda and me. In her first CEO letter she explores some of what she has learned in her first two years on the job. You can read a condensed version below, or the full letter here. – Bill Gates

One question unites us at the Gates Foundation: What if?

What if infectious diseases no longer devastated poor communities? What if women and girls everywhere were empowered to transform their lives? What if all children had an equal opportunity to reach their full potential?

Each question stems from our core belief that all lives have equal value. It’s been so inspiring to help uncover answers to them since I joined the Gates Foundation two years ago.

Everything I do is driven by the fact that the lives of fellow human beings are at stake—and we can do something about it. Although I still think of myself as a newcomer to the foundation, I’ve come to understand that everything we do is informed by a common approach.

It starts with Bill and Melinda, who guide our vision and bring crucial priorities to the global stage. We align our work with shared global goals and push ourselves to confront emerging challenges. We welcome all perspectives and embrace new ideas that offer better ways to tackle complex issues.

Above all, we depend on partners. What’s inspired me most during the past two years is how often our partners show us what’s possible.

Tobacco is a good example. It’s the only product that, when used as directed, will kill half of all users. Nearly 6 million people die of tobacco-related diseases each year—the vast majority in developing countries.

The Gates Foundation has committed over $225 million to partners working to address the tobacco epidemic in Africa and Asia. And we’re seeing progress in countries like the Philippines, where a significant tobacco tax increase has lowered smoking rates—particularly among 18-24 year olds and the very poor.

Partners are central to the fight against polio, malaria, HIV/AIDS, and tuberculosis, too. But it was progress against Human African trypanosomiasis—sleeping sickness—that caught my attention.

One of the neglected tropical diseases that afflict more than a billion people in developing countries, sleeping sickness endangers millions in sub-Saharan Africa.

But we can eliminate this disease. There were nearly 300 cases in Uganda in 2006. In 2013, there were 10. While new diagnostic technologies and drugs are important, it’s private sector partners that provide the resources and expertise—not to make profit, but because it’s the right thing to do.

Education is another area where partners are essential and our focus on evidence-based learning is apparent.

We firmly believe that education is a bridge to opportunity and that students thrive when held to high expectations. We support the Common Core State Standards to help set those expectations.

Unfortunately, our foundation underestimated what teachers need to implement them, as too many districts have struggled to identify Common Core-aligned teaching materials.

This is where partnership matters. No one knows teaching better than teachers. So we’re supporting the work of EdReports.org to provide teacher-led reviews that will help educators find high-quality instructional materials so that teachers can make the most of their expertise and experience.

Partners on the frontlines are particularly inspiring. Last year, I met Haliru Usman, a health officer in Nigeria who collects sewage samples to test for the polio virus. Health workers like Mr. Usman are vital to the fight against polio.

In 2015, Nigeria didn’t record a single case of polio, and for the first time, Africa was polio-free for an entire year.

Now, as the world focuses on Pakistan and Afghanistan—the final frontiers of polio eradication—we again find ourselves asking “what if?”

What if we continue to apply the expertise of great partners and the lessons we have learned to other challenges?

It’s not hard to imagine how much more we will achieve.