David Greenberg is a history professor at Rutgers University.

David Greenberg is a professor of history at Rutgers University. His books include “Republic of Spin: An Inside History of the American Presidency” and “Nixon’s Shadow: The History of an Image.”

Of all the forces that revolutionized society in the 1960s — the civil rights struggle, the antiwar movement, the Beatles — none mattered more than the Supreme Court. The court’s confident activism under Chief Justice Earl Warren not only bequeathed Americans a Christmas tree’s bounty of new rights, it also furnished traditionalists with a target in assailing the overreach of unelected liberal elites. And no Warren court ruling prompted greater ridicule than Justice William O. Douglas’s assertion, in the 1965 case Griswold v. Connecticut, that “specific guarantees in the Bill of Rights have penumbras, formed by emanations from those guarantees that . . . create zones of privacy.” On this famously (or infamously) insubstantial turf came to rest the establishment of a “right to privacy” that the court would use to legalize, in this instance, birth control and, eventually, abortion, gay sex and more.

But Douglas’s argument, if intellectually acrobatic, wasn’t without legitimacy. As the historian Sarah E. Igo reminds us in her masterful (and timely) new survey, “The Known Citizen: A History of Privacy in Modern America,” amendments in the Bill of Rights do implicitly recognize privacy rights — specifically the Third (on the quartering of soldiers), Fourth (barring unreasonable search and seizure) and Fifth (against self-incrimination). In fact, the high court had rejected as early as 1886 “all governmental invasions of the sanctity of a man’s home and the privacies of life.” The question in 1965 wasn’t so much whether citizens were constitutionally entitled to privacy but what precisely that right should encompass. Griswold, while surely a landmark, did not resolve that question. Critics at the time wondered whether the new constitutional allowance would cover protections from government surveillance, employer-mandated psychological testing, invasive policing methods or even telemarketers. Some charged that Douglas had misnamed the right he plucked from the penumbral ether: Perhaps, they said, he should have spoken of the “dignity of the individual” or “the right to be left alone.”

That latter phrase, legal scholars will recognize, appeared in the seminal 1890 Harvard Law Review article by future Supreme Court justice Louis Brandeis and his law partner Samuel Warren, “The Right to Privacy” — the point where Igo essentially begins her story. The attorneys proposed this right in response to newly aggressive forms of journalism that were turning individuals’ trysts and debaucheries, or even mere gossip, into headline fodder. The Gilded Age saw the advent of keyhole journalism, instantaneous photography, tappable telephones, surreptitious letter-opening and the prying moralism of sex crusaders like the notorious postal inspector Anthony Comstock. Even picture postcards, Igo relates in one of many humorous and eye-opening vignettes, came under fire for enabling, one magazine’s editors wrote, “servants and landladies to have the full benefit of our private matters.”

As this diverse mix of threats suggests, the right to privacy has from the start been something of a muddle, or maybe a smorgasbord — a series of distinct but somehow related entitlements to be free of society’s intrusions. “The Known Citizen” shows us that Americans have invoked “privacy” to shield our papers, correspondence, families, homes, physical likenesses, health, sexual practices, personal relationships, conversations, whereabouts, purchasing habits, Internet browsing and even the history of our behaviors. Incursions upon it, meanwhile, have come from nosy neighbors and the federal government, from corporations and journalists, from law enforcement officers and parents of teens. (An enticing footnote cites a book called “Get Out of My Room!: A History of Teen Bedrooms in America.”)


“The Known Citizen,” by Sarah E. Igo (Harvard University Press)

One group that plays a strikingly large part in Igo’s account is social scientists. These experts, who probe our lives to learn and catalogue all manner of data about our habits and preferences, also provide a bridge from her previous book, “The Averaged American: Surveys, Citizens, and the Making of a Mass Public,” which showed how the rise of polling and behavioral science surveys altered how Americans thought of themselves in relation to one another. “The Known Citizen” is thus a sequel of sorts, as Igo moves from the public to the private. The new question is to what degree we can insulate ourselves from those regulating pressures of society — or even if we can do so at all.

Privacy is clearly a protean concept, and Igo deftly reviews the definitions that scholars have offered in their efforts to cage its elusive essence. She judges these attempts helpful but less than conclusive. Her own ambitious solution is to embrace privacy’s multifariousness. In her marathon trek from Victorian propriety to social media exhibitionism, she recounts dozens of forgotten public debates — from the use of fingerprinting to find criminal suspects to the invention of Social Security numbers to track workers’ accrued savings; from the 1950s vogue for personality tests to assess employees to the Watergate-era fears of government surveillance. Collectively, they show the flexibility of privacy as a tool in seeking to limit society’s gaze, whatever forms it might take.

As in most academic works of intellectual history, the main actors here are ideas and theories. Narrating their history inevitably poses the challenge of how to forge compelling reading from intangible concepts. Igo rises to the occasion most effectively in those passages that spotlight particular people. One fascinating account deals with Laud Humphreys, a closeted gay Episcopal minister whose 1968 sociology dissertation explored homosexual hookups in public restrooms, known as “tearooms,” and was published as a book in 1970. Humphreys’s research exposed elaborate rituals fashioned in this demimonde amid the need to maintain privacy in the face of a censorious wider culture. Igo’s keen nose for irony shows up in her focus on Humphreys’s own unethical intrusions upon his subjects’ privacy — first by abetting their assignations as a lookout, or “watchqueen,” and then by secretly noting their license plates in order to track them down and interview them later under false pretenses. More fascinating still, Humphreys’s research — coming on the heels of controversial experiments by psychologists Stanley Milgram and Philip Zimbardo — fed into an entirely new privacy row, about what kind of disclosure social scientists owed to their subjects.

Igo’s final chapters chronicle a threat to privacy coming not from government or big business but from ourselves. Our current culture of disclosure and self-disclosure has fed a craze for confessional memoirs, stoked the news media’s willingness to report on politicians’ and celebrities’ private lives (and private parts), and flooded our screens with ordinary citizens’ oversharing about their illnesses, their kids and their sexual encounters with Aziz Ansari. But just when it seems that she might conclude, prematurely, with a verdict about privacy’s demise — that we’ve gone from the fear of Orwell’s Big Brother to the self-display of television’s “Big Brother” — she underscores that our contemporary zeal for publicity has co-existed alongside a renewed anxiety about its limits. Since the 1990s, Congress has passed laws safeguarding the privacy of, among other things, our video-renting habits, license plates, health records and children’s data. While I was writing this review, Google emailed me about its privacy policy updates, I heard a news report on the dangers of facial-recognition software, and another story told how navigation apps are leading motorists to speed through previously tranquil suburban streets.

What unites these sundry assertions of privacy is their claimants’ common complaint that they deserve some freedom from the proliferating intrusions on the self posed by a society that has become, over the past century and a half, more modern, organized, given to recordkeeping, technologically capable of monitoring us and inquisitive. Igo’s title comes from a poem by W.H. Auden, “The Unknown Citizen,” about a seemingly unremarkable midcentury man whose life — like everyone’s nowadays — was studied and recorded by government agencies, corporations, public opinion researchers and social psychologists, and yet who remained, Auden suggests, unknown in any true sense. As a society, we want to learn as much as we can about ourselves; as individuals, we seek to preserve a margin of anonymity, a sliver of the unknown.

Over time, Igo argues, Americans have largely judged the rewards of social knowledge to outweigh the liabilities. As much as we have lobbied for — and even inscribed into the Constitution — a right to privacy, we’ve chosen to countenance practices of observation, surveillance and study that will help us in “reporting the news, protecting national security, tracking public health and social welfare, understanding human psychology, improving commercial efficiency” and more. Igo’s research and conceptualization of this topic are utterly original, and yet in some sense hers is a story as old as Adam and Eve: We are undone by our quest for knowledge.

The Known Citizen
A History of Privacy in Modern America

By Sarah E. Igo

Harvard.
569 pp. $35