Book excerpt: On a typical day, you might make a call on a cell phone, withdraw money at an ATM, visit the mall, and make a purchase with a credit card. Each of these routine transactions leaves a digital trail for government agencies and businesses to access. As cutting-edge historian and journalist Christian Parenti points out, these everyday intrusions on privacy, while harmless in themselves, are part of a relentless (and clandestine) expansion of routine surveillance in American life over the last two centuries-from controlling slaves in the old South to implementing early criminal justice and tracking immigrants. Parenti explores the role computers are playing in creating a whole new world of seemingly benign technologies-such as credit cards, website "cookies," and electronic toll collection-that have expanded this trend in the twenty-first century. The Soft Cage offers a compelling, vitally important history lesson for every American concerned about the expansion of surveillance into our public and private lives.