Ms. Tufekci, a computer programmer who became a sociologist, sounded an early alarm on the need for protective masks. It wasn’t the first time she was right about something big.

Much of the confusion around masks stems from the conflation of two very different uses.

China’s use of surveillance and censorship makes it harder for Xi Jinping to know what’s going on in his own country.

People complain that going to the shore is a careless act during a pandemic, but the science so far suggests otherwise.

How is it that six months into a respiratory pandemic, we are still doing so little to mitigate airborne transmission?

That’s not what they’re for.