Across the industrialized world, millions of people live with sparse human contact, putting their well-being at risk. Does social media drive loneliness, or help to cure it? How does loneliness alter the brain, and how can we treat this condition?

Muslim Americans — especially those who work in government or in other ways to counter radicalism and terrorism — feel caught in the middle. Much of American society questions their patriotism, while their own communities question their loyalty.

Madison's legacy matters today more than ever. As founding genius he made the Constitution to avoid faction. Then he discovered the real world required parties — so he founded one and became a partisan.

In our politically charged climate, it’s not uncommon to hear about impeachment. Harvard Law professor Cass Sunstein offers a nonpartisan, historical guide — with some reverence — and even awe, for our constitutional order, and for the power it gives We the People.

Walter Isaacson is fascinated by innovators — the kinds of geniuses whose ideas have transformed industry, science, and society. Albert Einstein, Steve Jobs, and Benjamin Franklin grabbed his attention in ways that allow us, as readers, to discover the depth and breadth of their brilliant thinking. Now comes Leonardo da Vinci.

Why do happily married couples cheat? Esther Perel, author of the new book "The State of Affairs: Rethinking Infidelity," talks with Hanna Rosin, co-host of NPR's Invisibilia.

World-renowned economist Jeffrey Sachs is distressed about the political and social atmosphere of the United States. With advances in technology, he says we can choose to do the ultimate good or create unimaginable disaster.

The “next economy,” or digital revolution, is restructuring every business, job, and sector of society. Tim O’Reilly, founder and CEO of O’Reilly Media, says we should be harnessing technology, rather than fearing it, to grow jobs and increase economic activity.

The tiny town of Norwich, Vermont, has likely produced more Olympians per capita than anywhere else in the United States. New York Times sports writer Karen Crouse traveled to Norwich to discover the town’s secret.

As Latino Americans emerge as the majority minority and the new mainstream, representing 18 percent of the US population, questions are emerging about how Latinos fit into the national narrative.