Bill+Melinda Gates Cofounders, Bill & Melinda Gates Foundation

IT WAS MARCH 2018, AND ONCE MORE BILL GATES found himself behind a podium.

- Clifton Leaf

In the previous few months, he had given one keynote address after another—in San Francisco, he’d urged drugmakers to focus on diseases that affect the poor as well as the rich; in Andhra Pradesh, India, he had preached the value of smallholder farms; in Abu Dhabi, he’d enjoined the Crown Prince and other princelings to continue their financial support for global health initiatives; in Cleveland, he’d promoted investment in better schools.

Now the world’s second-richest man and foremost itinerant advocate for the poor was in Abuja, Nigeria, talking about the same theme that had underlain all of these speeches: the need to invest in “human capital.” Among those gathered at the conference center, in the shadow of the Aso Rock Presidential Villa, was the Nigerian President himself, Muhammadu Buhari, and what seemed like the entire seat of government, from legislative mandarins to a full house of governors and business leaders—all primed to hear from a man who had, so far, lavished the country with $1.6 billion in grants through his eponymous foundation.

Two months earlier, the Bill & Melinda Gates Foundation had taken the unusual step of absorbing a $76 million IOU Nigeria owed to Japan, for money Nigeria had borrowed to fund a polio eradication effort. The progress there had been striking. In 2012 the country had more than half of the worldwide cases of this paralyzing disease; that number had since been cut to zero.