Two mathematicians have proved that a straightforward question—how hard is it to untie a knot?—has a complicated answer.

Varying the format of comprehension checks guides students to demonstrate learning and provides teachers feedback on progress ...

How a 1950s study of social class and mental illness in New Haven changed the way people thought about mental health.

Peter is a writer and editor for the CNET How-To team. He has been covering technology, software, finance, sports and video games since working for @Home Network and Excite in the 1990s. Peter managed ...