NOVA reports on the potential danger of modern computers that gather "routine" information about our daily lives as we buy things, go to the hospital, or make donations. Computers can know more about us than our closest friends. NOVA examines how much of that personal information is readily shared with other computers.

A great secret lies locked inside the master violins created by Italian craftsmen like Antonio Stradivari in the 17th and 18th centuries. Now, a Wisconsin physicist, working alone in his cellar, may have solved the violin mystery.