A history of civilization could be written in fertilizers. And the history of guano—bird poop—tells us a lot about slavery, imperialism, and U.S. expansion.

A weekly deep dive into the scholarship around a current news story. This week: Barbie.

The sweet potato is a New World food that spread around the world, including across the Pacific before the Europeans got there.

Do we really need to drink so much milk?

Recent findings narrow the period in which both Neanderthals and modern humans existed together.