Even the most devoted Baker Street Irregular or Baker Street Babe must have trouble keeping up with the frenetic celebration of Sherlock Holmes and his creator Arthur Conan Doyle—the movies and TV series, the volumes of letters and diaries, the special editions of the canonical stories, the multiple collections of “new” cases, and the biographical and critical studies galore.

This past spring alone brought us several excellent works, including Michael Sims’s Arthur and Sherlock: Conan Doyle and the Creation of Holmes and Lyndsay Faye’s The Whole Art of Detection: Lost Mysteries of Sherlock Holmes. Stephen Fry, no less, recorded audiobook versions of the four Holmes novels and all 56 stories (although some are missing from the version available in the United States). And among this summer’s forthcoming treats will be Mattias Boström’s much-anticipated From Holmes to Sherlock: The Story of the Men and Women Who Created an Icon.

Given such abundance, it would be easy to overlook Through a Glass, Darkly. Still, there are several reasons to pay this entertaining book some attention. First of all, it focuses not on Conan Doyle’s writing but on his troubling, even embarrassing, belief in spirits, séances, and fairies. Second, it provides a potted history of spiritualism in the late 19th and early 20th centuries. And third, Stefan Bechtel and Laurence Roy Stains write brisk, sprightly prose, just as you would expect from brisk, sprightly magazine journalists. In fact, their book aspires to be “a jolly romp, rather than a scholarly treatise.” While the phrase “a jolly romp” may provoke a shudder, Through a Glass, Darkly actually does deliver plenty of excellent literary entertainment.

Following some introductory preliminaries, Bechtel and Stains begin in earnest with a dramatic account of the birth of spiritualism. In 1848, the Fox family, residing in upstate New York, grew increasingly frightened by inexplicable noises in the house they were renting. One night, though, daughter Kate noticed a pattern to the sounds. So, on an impulse, the girl shouted out, “Here, Mister Splitfoot, do as I do!” She then snapped her fingers twice “and two raps immediately followed, apparently out of thin air.” When sister Margaret clapped her hands four times, “four raps immediately followed.” A still shaken but now intrigued Mrs. Fox took up the game—“How old is my daughter Margaret?”—and back came 14 raps. “How old is Kate?” Twelve raps.

After the Fox family finally moved, the mysterious noises followed them to their new home. Eventually, Kate and Margaret, and later their much older sister Leah, acquiesced in their destiny as mediums. But were they really human doorways to the spirit world? Late in life, Margaret confessed that everything had been faked, even demonstrating how she produced the rapping sounds by cracking her big toe. That should have settled the matter but, not long before she died, Margaret firmly recanted her recantation, now asserting that she’d been bribed by nonbelievers. As jesting Pilate famously asked, “What is truth?”

By the later 19th century, spiritualism had grown into a worldwide movement and séances were commonplace, even family affairs. The whole movement was dominated by women, Bechtel and Stains note, many of whom were also active in the suffragist cause. Though not believers themselves, Elizabeth Cady Stanton and Susan B. Anthony affirmed that “The only religious sect in the world . . . that has recognized the equality of woman, is the Spiritualists.”

Meanwhile, in Britain the decline of traditional religious belief, combined with renewed scientific interest in the supernatural, led to the 1882 founding of the Society for Psychical Research, a body devoted to investigating the evidence for anything uncanny, from haunted houses to astral projection. Arthur Conan Doyle, a newly minted physician and aspiring writer, soon joined. Over the next three decades he would attend lectures and table-tipping soirées, read books with such deliciously evocative titles as Footfalls on the Boundary of Another World and Phantasms of the Living, and keep his mind open to the possibility of after-death survival. Might he have also experienced some precognitive hint of what was to come? His brother Innes once remarked—at a time when Conan Doyle, by then a world-famous author, was much involved in public affairs—that “it would be strange if your real career should prove to be political and not literary.” To which Arthur, preoccupied with a letter he was writing, immediately shot back, “It will be religious.”

In fact, Conan Doyle would pass the last 14 years of his life as the St. Paul of spiritualism. So far as can be determined, his conversion occurred in 1916 after Lily Loder-Symonds, a friend of his second wife, Jean, proved to be a sensitive medium. So great were her powers that she was able to repeat the gist of an “extremely personal conversation” that Conan Doyle had had with Lady Jean’s brother Malcolm many years earlier. There was, apparently, no possible way she could have known about this conversation. As Conan Doyle concluded, any rational explanation would be more farfetched than one presuming psychic abilities. That said, a skeptic might suggest that Malcolm told his sister about the conversation and Jean then told her friend Lily. O ye of little faith!

Still, by the middle of First World War, the creator of Sherlock Holmes had grown convinced that spiritualism was of the greatest benefit to mankind. After all, it removed the fear of death by providing proof that, somehow, we live on in the Other World—or Summerland, as it was sometimes called. What’s more, numerous séances revealed that not only our spirits but even our personalities survive the grave. What knowledge could be of more comfort to the families of soldiers blown to pieces in the trenches or to those who had lost loved ones during the devastating influenza pandemic of 1918?

Being a man who acted on his convictions and always lived up to his motto “Steel true, blade straight,” Conan Doyle was soon preaching the spiritualist gospel from lecture platforms all over the world. Early on, he even debated a onetime Franciscan priest turned atheist named Joseph McCabe. Bechtel and Stains see the humor in this: “A former friar argues for a godless universe, while the creator of the supremely rational detective Sherlock Holmes claims that we can talk to the dead.” The debate itself assumed a surreal, tent-revival kitsch: “As Queen’s Hall filled that night, each man was backed up by his chosen supporters onstage with him: fifty spiritualists to Conan Doyle’s right, fifty atheists to McCabe’s left.” Which the sheep, which the goats? By the end of the evening, the debate was declared a draw.

The middle part of Through a Glass, Darkly tracks some of the more colorful figures in spiritualist history, naturally zeroing in on the celebrated D.D. Home—the model for Robert Browning’s hypocritical “Mr. Sludge, ‘The Medium’ ”—and the flirtatious Mina Crandon, better known as “Margery,” her nom de séance. There’s also a chapter about the two young girls who demonstrated—with photographs—that there really were fairies at the bottom of the garden, or at least in the woods near their home. These 1917 pictures of the so-called Cottingley Fairies now look egregiously fake, but Conan Doyle and even wiser heads thought them real. Only in 1986 did one of the girls, now a very old lady, explain how she and her cousin fabricated the pictures as a lark, then found their joke taken seriously.

The last third of this jolly romp focuses on Conan Doyle’s friend and ideological adversary Harry Houdini. The famous mantra of The X-Files—“I want to believe”—neatly sums up the great escapologist’s initial attitude toward spiritualism. In particular, Houdini longed to make contact with his dead mother. Unfortunately, to his knowing eye, all the mediums resorted to familiar stage tricks. Before long, this self-appointed scourge of the spiritualists was regularly exposing the fraudulent. On one notable occasion he even tried to show Conan Doyle that anything a medium could do, a magician could do better.

First, Houdini brought out a small slate, which was subsequently suspended from his apartment’s ceiling so that it floated in the air. Conan Doyle was then asked to select a cork ball from one of several and immerse it in some white ink. Following this, the author of The New Revelation and Pheneas Speaks was ordered to leave the building, walk a couple of blocks, and jot a phrase or short message on a scrap of paper. When Conan Doyle returned, Houdini told him to fish the cork ball from out of the ink and hold it up to the free-floating slate. Immediately, “the white ball appeared to attach to the slate, as if it were magnetized, and then it began to move across the slate, spelling out words as it went.” The words spelled out were “Mene, mene, tekel, upharsin”—the memorable Old Testament judgment written by a gigantic hand upon a wall during Belshazzar’s feast. They were precisely the words Conan Doyle had scribbled on his piece of paper.

Through a Glass, Darkly closes, naturally enough, with the deaths of Houdini in 1926 and Conan Doyle in 1930. Both promised to make contact with loved ones from the other side. Did they? One medium appears to have learned certain code words only the magician’s wife Bess would recognize, but she suspected chicanery. Another medium, before a spiritualist jamboree at Royal Albert Hall, announced that an invisible Conan Doyle was in their midst and wished to deliver a private communication to his wife. What that whispered message said was never revealed by Lady Jean.

While Through a Glass, Darkly lacks the heft of Ruth Brandon’s magisterial (and quite wonderful) history The Spiritualists, it also eschews the mocking skepticism of modern-day debunkers, such as Martin Gardner. Instead, its agnostic authors proffer a series of lively set pieces drawn from the history of spiritualism, as well as a sympathetic account of how the creator of Sherlock Holmes solved, at least to his own satisfaction, the greatest mystery of them all.

Michael Dirda is the author, most recently, of Browsings . His On Conan Doyle won the 2012 Edgar Award for biography and criticism.