On the night of April 6, 1744, one of the most remarkable thinkers of the eighteenth century underwent an astonishing spiritual crisis. That night, Emanuel Swedenborg, a fifty-six-year-old Swedish scientist and statesman, experienced a visitation by Christ. Swedenborg, who was living in London at the time, had already spent several weeks experiencing unusual states of consciousness, triggered by the kabbalistic disciplines he had learned from Rabbi Samuel Jacob Hayyim Falk and by the erotic spiritual exercises he had gleaned through his association with the Moravian Chapel on London’s Fetter Lane. A no-nonsense scientist intent on pinpointing the soul’s location in the human brain, Swedenborg also had a long interest in the occult, and in the weeks leading up to his crisis, he had studied and practiced the sexual meditations—a kind of Christian Tantra—devised by the eccentric Count Zinzendorf, leader of the Moravians. Yet the strange altered states and remarkably vivid dreams familiar to Swedenborg didn’t prepare him for the events of that fateful evening. After a “psychic storm” erupted with great claps of thunder and a hurricane-like wind threw him from his bed—his own account suggests he had an out-of-the-body experience—Swedenborg found himself “face to face” with Christ. For a deeply religious man like Swedenborg, it was a powerful and disturbing encounter.

Looking at Christ’s smile, which Swedenborg thought was as it must have been “when he lived on Earth,” Swedenborg was surprised to hear the Lord ask if he had a “clean bill of health,” a reference to a time when Swedenborg was almost hung for breaking quarantine during the plague. Humbled, Swedenborg replied that he, Christ, knew the answer to this better than he did himself. Christ agreed and replied, “Then do.” Swedenborg took this to mean “Then do.” Swedenborg took this to mean he was to fulfill his promise to abandon his scientific work and to concentrate instead on investigating the spiritual worlds within.

Whether Christ meant this or not, Swedenborg took the injunction to heart. For the rest of his life, he mapped out the strange geography of the interior realms, covering a terrain that included not only other planets but also heaven, hell, and an intermediary sphere Swedenborg called the spirit world.

Although in his day he was fêted by nobility and he later inspired individuals as diverse as, to name just a few, the poets William Blake and Charles Baudelaire, the playwright August Strindberg, the composer Arnold Schoenberg, and the Zen master D.T. Suzuki (who called him the Buddha of the North), outside the realms of parapsychology and the history of dissident Christian sects, Emanuel Swedenborg is little known today. This is unfortunate; his work, both as a scientist and as a religious thinker, deserves wider recognition.

If his name does ring a bell, it’s usually as the inspiration for an eccentric form of Christianity, the New Church, to which William Blake once belonged (and with which, incidentally, Swedenborg had nothing to do, as the church was founded after his death). Others may know that Swedenborg wrote dauntingly long books, depicting in precise detail the conditions of life in heaven and hell, information about both places reaching him through his many visits there, which were taken during the unusual trance states he had mastered. Still others may recall that Swedenborg provides some of the most convincing evidence for precognition and clairvoyance. Among other remarkable examples, he accurately predicted the exact date and time of his death. On another occasion, he “saw” a fire break out in Stockholm while he was at a dinner party three hundred miles away. His fellow guests were startled as Swedenborg reported the spread of the flames and shared his relief as he announced that the fire had stopped just doors away from his own home. Days later, Swedenborg’s report was confirmed by a messenger. In a time without telephones, email, or fax machines, how he could have known of the fire while he was hundreds of miles away remains a mystery.

Yet these sensational reports of Swedenborg’s psychic gifts, found in most histories of the paranormal, often overshadow his important philosophical and spiritual insights. Whether or not Swedenborg actually visited heaven and hell, his accounts of life in the angelic or devilish spheres, collected in his appropriately named Heaven and Hell, often provide profitable insight on how best to lead our lives here on earth. This is why people like Helen Keller, Ralph Waldo Emerson, Jorge Luis Borges, and the Nobel Prize winner Czeslaw Milosz read him deeply and advised others to do the same. I took that advice myself and eventually wrote a book about Swedenborg. While researching an earlier book on the influence of the occult on Western literature, I found that more often than not, the trail linking a particular poet or novelist to the occult led to this Scandinavian Da Vinci. This happened so often that I decided to find out what was so special about him. I’m glad I did.

Although his religious and spiritual work receives the most attention today through scholars and groups dedicated to his ideas, Swedenborg’s scientific work still offers much reward, a point I argue in my book Into the Interior: Discovering Swedenborg. Born in 1688 into a deeply religious family, Swedenborg began his career as an engineer, and his practical hands-on work offers a good argument against the clichéd notion of mystics as inept unworldly types. The many practical tasks facing Swedenborg included designing the locks on the Trollhättan Canal, which links Stockholm with the North Sea; devising Sweden’s first saltworks; and a remarkable feat of engineering that had Swedenborg moving the Swedish navy some fifteen miles across land during a war with Norway. It was around this time that Swedenborg was made a special assessor of Swedish mines, a demanding position he fulfilled conscientiously along with his other duties as a member of the Swedish court. He also started the first Swedish scientific journal, Daedalus Hyperboreus, named after the mythical Greek inventor. It was a kind of Popular Mechanics of the day, to which he contributed articles on topics ranging from metallurgy to mechanical inventions. Swedenborg spent years traveling across Europe, meeting some of the most important minds of the time, and his reports thrilled the members of Sweden’s first scientific society, the aptly named Guild of the Curious.

Swedenborg’s more speculative scientific work led him to anatomy and the mysterious machinery of the body, as well as to the equally intriguing riddles raised by cosmology, the origin and structure of the universe. He wrote reams on both, and in several instances his insights anticipate many later discoveries. In his studies of the brain, for example, Swedenborg was the first to recognize the existence of neurons. He also recognized the importance of the frontal lobes for the higher psychic functions like reason and rationality, and he anticipated the findings of split-brain research, arguing that the brain’s left hemisphere was “masculine” and housed our rational minds, while the right was “feminine” and was the seat of emotions. As many have done after him, Swedenborg argued for the need to integrate these often opposing halves. He also noted the significance of the little understood cerebellum, the protocerebrum located at the back of the skull, which some theorists argue is the seat of paranormal and mystical experiences.

In cosmology, Swedenborg was the first to posit the nebula theory of solar and planetary formation—in which stars and planets start out as gaseous clouds—credit for which is usually given to the French mathematician Pierre-Simon Laplace and the German philosopher Immanuel Kant. There’s a good argument, however, that Kant first got the idea from reading Swedenborg. Swedenborg’s countryman and fellow scientist, Nobel Prize winner Svante Arrhenius, argued that among Swedenborg’s astronomical anticipations was the idea that the length of the orbits of Earth and other planets around the sun has increased over time, and that Earth’s rotation—and hence the length of a day—has also increased. He also argued that Swedenborg first noted that the stars spin on their axes and that they circle the Milky Way. Swedenborg also posited the notion of other galaxies and believed that these themselves form immense stellar systems—an idea common today but unheard of at that time. He also seems to have anticipated the kinds of stars called pulsars, which emit bursts of radiation, and to have put forth a strong version of what is known as the anthropic cosmological principle, which argues that a universe such as ours must produce intelligent life. Swedenborg trumped this by arguing that the universe was created in order to produce beings like ourselves. This was so because heaven, at least according to him, is populated by human beings who, after death, become angels. One planet alone couldn’t produce enough people to populate heaven properly, so Swedenborg argued that there must be myriad worlds housing intelligent beings.

Although thinkers as significant as the German poet and scientist Goethe were influenced by Swedenborg’s scientific writings, it was his religious and spiritual texts that had the most effect. Written in a dry, often pedantic style, Swedenborg’s depictions of heaven, hell, and the spirit world have inspired countless readers since they first appeared nearly three centuries ago. Most radical at the time was his contention that rather than actual places one goes to after death, heaven and hell are states of being, that is, inner states of mind. We enter them, he argued, not as a reward or punishment for our virtues or sins, but through our own choices. Centuries after Swedenborg first proposed this idea, the philosopher Jean Paul Sartre, in his play No Exit, would famously say that “hell is other people.” Had he read Swedenborg, Sartre would have known that he was only half right. For Swedenborg, hell and heaven are in all of us; it’s our choices in life that determine in which one we spend most of our time.

Swedenborg “traveled” to heaven and hell through his remarkable ability to enter and remain in trance states for long periods. As I argue in my book, he was adept at maintaining the curious mental state called hypnagogia, the strange twilight realm in between sleeping and waking that we enter every night. Most of us pass through this condition quickly and for the most part are unaware of it. Yet Swedenborg was able to maintain this altered state for hours. In the hypnagogic state, weird half-dreams—similar but not identical to lucid dreams—emerge in which we perceive vivid landscapes or hear strange voices. In this curious condition, Swedenborg would encounter angels, who took him on tours of heaven or of hell.

Swedenborg’s heaven is both very familiar and very strange. In heaven, angels live in houses, eat, and work—no angel is idle, Swedenborg said—and his depictions of it seem similar to Earth, only much better. The houses are beautiful, and no matter which way they turn, every angel faces God. They also make love. In fact, in one of his last books, Conjugial Love, written while in his eighties, Swedenborg argued that in heaven, angels engage in mutually satisfying and apparently continuous lovemaking, achieving a gratification sadly rare on Earth. In heaven, we meet our true soul mate, which more often than not isn’t the one we knew on Earth. Although he had mistresses, Swedenborg himself never married, and some believe this is because he was in love with a married woman and was patiently awaiting their union in heaven. Yet while this heaven seems like a kind of fantasy—nevertheless, one more interesting than conventional ideas of cherubs strumming harps—conditions there are very different from those here on Earth. For one thing, time and space do not exist, or exist only as “states.” Distances in heaven are measured by degrees of empathy, and like-minded spirits are “near” each other wherever they may actually be. Time is similarly measured in degrees of consciousness, or “nearness” to the Divine, the heavenly center, radiating into infinity.

On the other hand, Swedenborg’s hell, which rivals Dante’s as a place of punishment, is an exhaustively unpleasant sphere. Inhabited by bickering souls who move about through rivers of excrement breathing noxious fumes and harrowed by insatiable and incessant desires, Swedenborg’s hell is rather like a theme park based on the paintings of Hieronymus Bosch. Yet, according to Swedenborg, the sad spirits who find themselves there had already inhabited hell while still alive, and the disgusting milieu they now occupy is really a projection of their own unrestrained lust and selfishness. One consolation is that souls in hell prefer it to heaven, which, to them, would indeed be a place of torment, a theme taken up in Bernard Shaw’s very Swedenborgian work, Don Juan in Hell.

Perhaps the most fascinating of Swedenborg’s mystical travelogues are those describing what he calls the spirit world. Here, souls newly dead awaken and slowly drift toward their final destination. What determines our place in eternity are what Swedenborg calls our true affections, those which truly motivated us in life. Although on Earth we can say one thing, yet think another—can smile when we hate someone’s guts—in the spirit world this is impossible. Here, what we are is the same as how we appear, or as the old saying goes, in the spirit world, “what you see is what you get.” We can’t kid anyone here, not even ourselves. Swedenborg had a lifelong aversion to hypocrisy and duplicity, and such false living is impossible in the spirit world. What is “real” about someone are his or her intentions, and in the spirit world, “absolutely everyone is resolved into a state in which he speaks the way he thinks, and displays in his expression and gestures what his intentions are.” (Clearly, a realm politicians would wish to avoid.) Indeed, Swedenborg was often surprised to bump into a bishop or two while his angelic guides showed him around.

Yet his intent isn’t to scare us into being good, a tactic that unless we really were good—unless, that is, our true affections were for the good, the true, and the beautiful and not for the acceptable, the plausible, and the fashionable—wouldn’t work anyway. Neither is Swedenborg deter-minist. Our true affection for the noble and selfless must be pursued; complacency won’t do. Swedenborg summed it up in a homely maxim: “Do the good that you know.” As in Hindu notions of dharma, this can mean simple tasks like doing the dishes or taking out the trash. When the Upanishads counsel us to do our own duty, no matter how humble, rather than that of another, no matter how grand, they offer very Swedenborgian advice.

Admittedly, Swedenborg’s prose can seem stilted and unappetizing. That he wrote in Latin may have something to do with this. That he also wrote at a time when the Bible was still at the center of Western thought also puts some distance between Swedenborg and us. It would be a shame if these hurdles prevented readers from encountering him. One reason I wrote my book was to get the gist of his ideas across to readers lacking the time to mine his work on their own. If some do feel like taking a stab at it, Heaven and Hell is the place to start. Forget whether or not Swedenborg’s descriptions are literally true and think of them as parables, encounters with the soul via a kind of Rough Guide to altered states. The effort won’t be wasted, and the attentive reader may find, as Swedenborg himself did, that the terrain is oddly familiar. As Swedenborg knew, we choose between one or the other several times a day.

Gary Lachman is the author of Into the Interior: Discovering Swedenborg (London: The Swedenborg Society, 2006) as well as other books on consciousness, culture, and the Western esoteric tradition. His most recent work is Politics and the Occult: The Left, the Right, and the Radically Unseen (Wheaton, IL: Quest Books, 2008).