New technologies are always a mixed blessing, their potential for good carrying with it the risk of evil. The deep challenge for a democracy is to develop legal rules, social practices and institutional arrangements that, at some reasonable cost, separate good from bad behavior. The exponential improvement in computation and communication technologies over the past few decades has posed this challenge in an acute form. Both large bureaucracies and determined individuals can now collect and organize huge amounts of information—and all of it, in one sense or another, is about all of us.

Protecting our privacy from the prying eyes and ears of government is the subject of Bruce Schneier’s “Data and Goliath,” whose title suggests an uneven struggle. JacobSilverman’s “Terms of Service” grapples with similar themes, though he focuses on commercial behemoths such as Amazon, Apple, Facebook, Google and Twitter, which relentlessly gather information about their customers. Both books, however, offer one-sided presentations.

It is not that these authors have nothing instructive to say about these problems. Mr. Silverman, a journalist, warns us to beware of “how companies try to embed pernicious language in their terms of service agreements,” leading consumers to give away their privacy rights unknowingly. Mr. Schneier, a security technologist and fellow at the Berkman Center for Internet and Society at Harvard Law School, is attuned to the smallest potential dangers: He points out (rightly) how easy it is to use metadata to identify by name participants in any medical study, or to track cellphone usage near the site of a labor dispute without a warrant. But both authors are unable to make intelligent trade-offs among individual privacy, national security and business efficiency.

Read more at The Wall Street Journal