One of my graduate school professors, commenting on a historian famous for his prolific reading and reviewing of recent work in American history, said, “We should be grateful to him. He reads all those books so the rest of us don’t have to.” On that principle, we owe profound gratitude to Michael Barkun, who has spent years immersed in some very strange publications and Web sites.

More than any other scholar in America, Barkun, a political scientist at Syracuse University, knows his way around the arcane world of contemporary conspiracy theorists. His 1994 book Religion and the Racist Right: The Origins of the Christian Identity Movement is highly regarded. The interests of the community he examines in this new work go far beyond garden-variety speculation about the Kennedy assassination or the death of Vincent Foster. These folks take seriously the existence of UFOs; FEMA concentration camps; the UN’s secret fleet of black helicopters; mind control through microchip implants; mysterious cattle mutilations; occult symbolism in the Washington, D.C., street grid; and satanic imagery in the Denver airport terminal. In this world the 19th-century “Protocols of the Elders of Zion” remains hot news, along with “MJ12,” a supposed secret memo describing the government’s UFO cover-up. “Let no crank be left behind” sometimes seems Barkun’s guiding principle.

Barkun gives us a Cook’s tour of this psychedelic world, pointing out how the many varieties of conspiracy theory have evolved, diverged and intersected. He plumbs the Internet, clearly a godsend to conspiracy theorists. There they can discover each other, share and critique each other’s ideas and create their own subculture, where the fact that outsiders find their notions utterly bizarre is irrelevant.

A Culture of Conspiracy is in the tradition of studies of the cultural underground, including such works as Norman Cohn’s Pursuit of the Millennium (1957), a survey of medieval apocalypticism officially rejected by the church, and Robert Darnton’s history of pornography, The Forbidden Bestsellers of Pre-Revolutionary France (1995). Students of 19th-century American sex reformers work a similar vein. Barkun’s venture into this genre has yielded impressive results.

In an opening theoretical discussion, he characterizes conspiracy belief as an attempt “to delineate and explain evil,” guided by three basic principles: Nothing happens by accident; nothing is as it seems; and everything is connected. Insisting on the cultural importance of “stigmatized knowledge,” he looks at the history of this tradition, going back to the Order of Illuminists founded in 1776 by Bavarian law professor Adam Weishaupt to free mankind “from all established religious and political authority.” The “Bavarian Illuminati” soon disappeared, but their ideas have enjoyed a rich afterlife among conspiracy theorists, in works often marked by anti-Semitic overtones.

In recent years, in a process of “improvisational millennialism,” this venerable strand of world-conspiratory speculation has been combined with theories of visitations by space aliens. Barkun traces this breakthrough to a “not entirely coherent” 1978 work by Stan Deyo, an American living in Australia. Far more influential in grafting UFO belief onto conspiratorial thought to form a “superconspiracy” theory was Milton William Cooper’s Behold a Pale Horse (1988), currently ranked 11,825 on Amazon.com, which means it is still selling nicely after 15 years.

Barkun devotes several chapters to the recent evolution of this hybrid superconspiracy theory, which includes a variant—derived from 1920s pulp fiction with an assist from Tolkien—in which the conspirators are not space aliens but reptilian creatures from Inner Earth who take on human form. Barkun finds a bright side to this development: if the sinister beings seeking to control the world come from UFOs or Inner Earth, more mundane villains are left off the hook. Indeed, anti-Semitic themes have declined with the injection of theories about aliens into the conspiracy scenario.

Demonstrating the patience of Job, Barkun only occasionally ventures a mild judgment. One Inner-Earth theorist, he suggests, “seems clearly to have been delusional”—an assessment that some might apply to practically every figure in the book. Where a less conscientious scholar might simply have dismissed this subculture as a realm of kooks, obsessives and the certifiably insane, worthy only of jeering ridicule, Barkun patiently discusses each book and Web site, tracing the elaboration of ever more fantastic theories. However bizarre, he argues, these ideas must be taken seriously, since they can influence action and, in diluted form, they work their way into the cultural mainstream.

Nevertheless, I pursued a running argument with Barkun: he was wasting too much intellectual energy on the lunatic fringe. (I thought of a nifty title for my hypothetical review: “Barkun Up the Wrong Tree.”) The big story in contemporary apocalypticism, I told myself, is not UFOs and creepy-crawlies from Inner Earth, but John Darby’s dispensationalism, which enjoys enormous influence, thanks to popularizations like Hal Lindsey’s The Late Great Planet Earth (1970) and the bestselling Left Behind novels by Tim LaHaye and Jerry B. Jenkins. Yet dispensationalism is only passingly noted by Barkun.

Questions of relative cultural influence are important. Oddly appealing as they are, Barkun’s wild improvisers are simply not in the same league with LaHaye and Jenkins, with sales of 55 million and counting. The Left Behind series is The Late Great Planet Earth on steroids. Borders, Barnes & Noble, Wal-Mart and Amazon.com, not to mention thousands of Christian bookstores, are selling these books like hotcakes, along with those of other Bible prophecy popularizers, including the indefatigable Lindsey.

Unlike Barkan’s dizzyingly eclectic theorists, the Left Behind books are firmly grounded in a view familiar to generations of fundamentalists. LaHaye and his “Pretribulation Research Center” in San Diego insist that the Book of Revelation offers a literal road map to coming events, complete with a darkened sun, falling stars, beasts from the sea, rivers of blood, Gog’s invasion of Israel, the drying up of the Euphrates and the Beast’s world dictatorship under the sinister number 666. For LaHaye, Revelation is no allegory or first-century Christian wishful thinking about Rome’s destruction. All of it will literally be fulfilled in the future. The Left Behind novels scrupulously follow this interpretation.

Dispensationalism’s political and cultural impact is indisputable. As Joan Didion has documented (New York Review of Books, November 6, 2003), Bible-prophecy believers constitute a vital segment of President Bush’s supporters, and Bush himself seems convinced that his elevation to the Oval Office and his every action since have been determined by God. Before announcing his candidacy, he met with leaders of the “Council for National Policy,” a shadowy right-wing Christian group of which Tim LaHaye is a co-founder.

The Internet is a great leveler, as Barkun notes, but not all Web sites (or books) are equal. Barkun believes that the Internet has enabled his improvisers to reach “a vastly broader audience.” But a proliferation of Web sites does not prove an expanded audience, and even by the most generous assessment of their influence, they lag far, far behind the Left Behind juggernaut.

Nevertheless, as I thought further about my distinction between the dispensationalists and Barkun’s “improvisational” crew, I decided that on the epistemological level the differences may not be so great. While most of Barkun’s theorists ignore the standard dispensationalist practice of documenting their scenarios with scriptural citations, biblical themes and imagery pervade their work. The appeal of Behold a Pale Horse, for example, certainly lies in part in its title, a quote from Revelation 6:8: “And I looked, and behold a pale horse: and his name that sat on him was Death, and Hell followed with him.”

The “new world order” conspiracy theories clearly draw upon the Revelation account of the Beast; abduction-by-aliens tales evoke the rapture; and persons who report messages from aliens offer a variant of numerous biblical accounts of direct communication from God. The reptiles from Inner Earth recall both the scorpion-like creatures who swarm from the bottomless pit in Revelation 9 and the Genesis account of Satan appearing as a serpent. Even the pariah status of these beliefs echoes a Christian theme: the truth is revealed to despised outcasts and ridiculed by the great. In short, the Judeo-Christian template of this material seems clear. Though Barkun briefly notes these connections, they bear further exploration.

To make the same point from the other direction: How different, really, are the bestselling popularizers writing within an ostensibly Christian interpretive tradition and Barkun’s non-Christian theorists? As Barkun notes, Pat Robertson’s 1991 bestseller The New World Order portrays history as a vast conspiracy originating with the Masons and the Bavarian Illuminati and continuing through the Rothchilds, the first Congress (which emblazoned that sinister motto Novus Ordo Seclorum on the Great Seal of the United States), the Federal Reserve Board, the UN, the Trilateral Commission and the Beatles. Arno Froese of Midnight Call Ministries, through many paperback books, Midnight Call magazine and prophecy conferences at pricey resort hotels, promulgates theories about computers, new surveillance technologies and Washington’s post-9/11 antiterrorist measures as anticipations of the Antichrist. These differ little from Barkun’s theorists. The convention that requires dispensationalists to cite biblical authority constrains them somewhat, but has not unduly limited them as they apply their imaginative powers to the hermeneutic task.

Lest we too readily dismiss conspiracy theorists, it is well to recall the record of real conspiracies, skullduggery and deception in recent public life. The 1940 Smith Act authorized concentration camps for dissidents in national emergencies. The FBI tapped Martin Luther King’s phones. The Atomic Energy Commission funded secret radiological experiments on institutionalized children. Star Wars researchers faked test results. Watergate, Iran-contra, corporate criminality, the mendacious arguments for the war on Iraq—the list of deceptions is a long one.

Nor does the notion of an all-powerful world system seem unduly bizarre in this era of global corporations, instant money transfers, gargantuan media conglomerates and the WTO. Indeed, the worldview of Barkun’s cast of characters parallels that of New Leftists of the 1960s, with their talk of the Establishment, or the contemporary work of Noam Chomsky. According to Amazon.com, buyers of Jim Marrs’s Rule by Secrecy: The Hidden History that Connects the Trilateral Commission, the Freemasons, and the Great Pyramids (2000) are also purchasing Chomsky’s World Orders Old and New (1996). The conspiratorial-minded, in short, find ample grist in contemporary history.

In our allegedly secular culture, one finds conspiratorial themes and alien visitors in The Day the Earth Stood Still (1951), Invasion of the Body Snatchers (1956) and, more recently, TV’s X-Files series (“Trust No One”), the Matrix films, Close Encounters of the Third Kind (1977) and E.T. (1982). As for popular receptivity to “stigmatized” knowledge, Barkun cites polls suggesting that about half of Americans believe in UFOs. And it is worth recalling that not so long ago a U.S. president’s schedule was being planned by an astrologer.

Barkun is certainly right to emphasize the way these ideas filter into the cultural mainstream, but caveats suggest themselves. As ideas are “diluted” for popular consumption they also change until, perhaps, like 19th-century homeopathic nostrums, they lose their potency. How large is the core group of true believers, and how does the process of diffusion beyond this core actually work? Did people who enjoyed the X-Files or Oliver Stone’s conspiracy-drenched JFK graduate to the “hard core” conspiracy material? Certainly some deeply conspiratorial works such as Behold a Pale Horse have won a large audience. Marrs’s Rule by Secrecy currently clocks in at an impressive 3,966 in Amazon.com’s sales rankings. Are these breakthroughs typical of a larger pattern, or rare exceptions? Clearly, no definite line separates Barkun’s theorists from the mainstream. They are simply particularly intense and single-minded advocates of ideas that in diluted dosages drip steadily into the nation’s cultural bloodstream.

Potent cultural forces do resist these conspiracy theorists, from skeptical ridicule to fundamentalist objections about their lack of a biblical foundation. In One Nation After All (1998), sociologist Alan Wolfe cautioned that we over-emphasize the extremes of American discourse and neglect the moderate middle ground. This reminder is worth keeping in mind.

Like all good works of scholarship, A Culture of Conspiracy raises questions and invites further research. For example, could not this conspiracy material be more fully placed in historical context? The first UFO sightings came amidst the postwar Red Scare, when the nation was obsessed with the fear of traitors among us. Government propaganda encouraged an apocalyptic worldview during the cold war, as it does now, when we wage an open-ended “war on terrorism.” And is it coincidental that “increasingly conspiratorial motifs” appeared in UFO speculation just after the Watergate scandal?

Does the psychiatric literature shed light on personality types that are particularly susceptible to conspiracy thinking, or on the appeal of Gnostic subcultures that claim to possess secret knowledge? What demographic or geographic patterns characterize this subculture? Beyond Japan’s Aum Shinrikyo, discussed by Barkun, do similar theories occur in other cultures? Within the U.S., how does this tradition relate to African-American conspiracy theories, from Elijah Muhammed’s teaching that whites are devils to the more recent myth that AIDS began as a white conspiracy to kill Africans, or Amiri Baraka’s suggestion that Jews had advance knowledge of the 9/11 attacks?

Barkun briefly raises an important point in his conclusion when he notes “the absence of formal organization” among these conspiracy theorists. Very few have founded institutions to perpetuate their beliefs. This remains a virtual community thriving on the Internet and discussing a common body of work, but otherwise unconnected. Here Barkun’s subjects differ markedly from the dispensationalists, with their strong institutional base in fundamentalist and charismatic churches. But lack of organizational structure has some advantages: it frees conspiracy theorists to modify and revise their theories at will, to disseminate them with lightning speed, and to win recruits unencumbered by any obligation to contribute to a formal institution.

One wonders to what extent these beliefs are transmitted across generations—a key element in the tenacity of apocalyptic beliefs embraced by established religious bodies. Children who grow up in dispensationalist churches are more likely to adopt these beliefs themselves. Does this process of generational continuity work when beliefs are purveyed on the Web or by books alone?

Finally, to draw on Robert Alan Goldberg’s Enemies Within: The Culture of Conspiracy in Modern America (2001), one wonders whether American culture particularly encourages this type of thinking. Conspiratorial strands certainly pervade our myths of origins. The New England Puritans saw themselves as escaping a corrupt established church. The Declaration of Independence denounces the wicked conspiracy led by George III—the “royal beast” of Thomas Paine’s Common Sense—to destroy American freedom. Historians Richard Hofstadter and John Higham have documented 19th-century nativist and conspiracy thinking. Barkun’s theorists, intent on smoking out the evil that threatens our beloved city on a hill, are a part of this deep-rooted tradition. If conspiracy thinking is indeed inscribed in our national DNA, what does that tell us? The paradox of “Trust No One” is that you cannot trust even the person who tells you to trust no one. One ends—as Tocqueville observed long ago—imprisoned within one’s self, viewing the outside world with narrow-eyed suspicion.

Studiously nonjudgmental for the most part, Barkun concludes on a somber note:

The danger lies less in such beliefs themselves . . . than in the behavior they might stimulate or justify. As long as the New World Order appeared to be almost but not quite a reality, devotees of conspiracy theories could be expected to confine their activities to propagandizing. On the other hand, should they believe that the prophesied evil day had in fact arrived, their behavior would become far more difficult to predict.

One is reminded of Pat Robertson’s recent comment in interviewing the author of a book denouncing the State Department: “If I could just get a nuclear device inside Foggy Bottom, I think that would be the answer.” And, as Barkun reports, before Timothy McVeigh parked that Ryder truck outside the federal building in Oklahoma City, he had visited not only the charred remains of the Branch Davidian site at Waco but also “Area 51,” the secret government installation in Nevada that fascinates conspiracy theorists. Ideas, even bizarre and marginalized ideas, do have consequences, and we ignore them at our peril. Barkun’s explorations, like the canary in the coal mine, warn us of what may lie ahead. Today’s bizarre theory may become tomorrow’s blueprint for action.