A couple of years ago, journalist Gay Talese published “The Voyeur’s Motel,” the true story of a motel owner who spent more than 30 years spying on his guests while they had sex. The case is now the subject of a Netflix documentary called “Voyeur.”

The personal devices we live with and depend on — our computers, tablets, smartphones and more— all share information about us. Randolph Lewis tells more stories about how we’re being watched in a book called “Under Surveillance.”