In this book, professor of English Brian McCuskey explores the role of Sir Arthur Conan Doyle’s character Sherlock Holmes in Doyle’s lifelong project of promoting Spiritualism as a scientific religious worldview. McCuskey locates the great detective within larger debates of the era between religion and science and rhetorical gambits about “the logic of logic.” He argues that Holmes effectively confused magical and scientific thinking, paving the way for Spiritualism’s scientific claims at the end of the nineteenth century, as well as dangerous conspiracy theories at the beginning of the twenty-first century.Although Holmes is presented as, and generally understood to be, a master of logical deduction, most of his conclusions are actually leaps of logic that only work within a fictional universe. As McCuskey writes, “Holmes’s observations are the projections of his own interior illumination. He gaslights everyone else’s reality” (62). So in the real world, when people attempt to “think like Sherlock Holmes” they are usually engaging in confirmation bias rather than logical deduction.McCuskey is not the first to point out that Holmes was not actually a very good detective. Steven Byington coined the term “The Sherlock Holmes fallacy” in 1903 to debunk conspiracy theories about the Jesuits (77). McCuskey’s research is fresh, however, in locating Holmes’ strange logic within larger nineteenth-century debates about religion and science. By making logic into a preternatural faculty, McCuskey argues, Holmes takes the “iron cage” of disenchantment described by Max Weber and makes it seem like a re-enchanted paradise rather than a prison (66). For example, he notes that the idea of a detective who is effectively omniscient because he has mastered the “limitless power of pure reason” (50) is essentially identical to Theosophical ideas of Masters who are omniscient through their powers of intuition. McCuskey views the iron cage as a prison, with Holmes the harbinger of numerous forms of dangerous pseudoscience, including Spiritualism.How Sherlock Pulled the Trick consists of an introduction followed by five chapters, arranged somewhat chronologically. Chapter 1, “Reason and Revelation, 1887,” examines debates in the London press about religion and science in the year when the first Holmes novel, A Study in Scarlet, was published. At that time, theologians were responding to Darwinism as well as higher criticism of the Bible and many rejoined by “turning science against itself,” framing scientific arguments as dogma and religious truth claims as empirically verifiable. It was during these debates about “the logic of logic” that Holmes was born.Chapter 2, “Reasoning Backward, 1881–1887,” follows Doyle’s religious development prior to the publication of A Study in Scarlet, exploring how he left his Catholic upbringing behind and became enamored with the idea of empiricism while in medical school. Chapter 3, “Theory and Preaching, 1887–1930,” looks at the development of Holmes and Doyle side-by-side up through Doyle’s death in 1930. Chapter 4, “Wonderful Literature, 1930–2020,” examines the culture that formed around Doyle and Holmes after the death of the author. People began to encounter Doyle at séances, and his widow and sons spent the rest of their lives working to defend Doyle’s characters from zealous fans. This chapter also contains a detour into the history of literary criticism surrounding the Holmes stories.Chapter 5, “Negation at Any Cost, 2001–2020,” considers the legacy of Holmes across such media as film, television, and social media. This chapter is the most significant to McCuskey’s overall argument and will likely be of the most interest to readers of Nova Religio. The author notes that Holmes is cited frequently by proponents of creationism seeking to introduce Intelligent Design theory into public schools. Holmes is also invoked by the 9/11 Truth movement in advocating for antisemitic conspiracy theories. Alt-right conspiracy theorist Mike Cernovich tweeted at his followers to “Read Sherlock Holmes” so that they could understand the logic of his conspiracy theories about Hillary Clinton. For McCuskey, these and other examples reveal the dangerous forces that are empowered when religion is treated as science and science is treated as religion.Historians of Spiritualism will likely be frustrated by this book, however, as it takes an entirely negative attitude toward Spiritualism. McCuskey frames Spiritualism almost as a mental illness writing that, “Joseph McCabe warned a century ago that the health of a democracy depends on the sanity of its citizens. Letting spiritualism alone is therefore bad public policy” (166). He notes the Spiritualist convert who killed her son and herself in 1922 so they could enjoy a more peaceful existence in the Summerland. Although Doyle commented on this murder-suicide, McCuskey implies that this is typical of belief in Spiritualism rather than an extreme anomaly among the millions of Spiritualists who were active in 1922.Nevertheless, this book is full of threads that could inform conversations in new religions studies if they were developed more fully. McCuskey’s argument is helpful for analyzing the role of fiction as a “plausibility structure” for supporting religious worldviews. At a séance held in 1931, the spirit of Doyle appeared and explained that mediums have the power to inadvertently create “thought-forms” that possess an independent existence and function as spirit guides. This revelation inspired Theosophist Ivan Cooke to speculate that Sherlock Holmes may have become such a thought-form. This account anticipates contemporary claims in paranormal discourse that fictional characters can become “tulpas” or otherwise gain an actual existence if enough people think about them.Doyle’s experiments with Spiritualism are also relevant to larger discussions on the mystical and paranormal experiences of fiction authors, including L. Ron Hubbard, Philip K. Dick, and Whitley Strieber. There are even implications for theories of failed prophecy. Doyle communicated with a spirit named Pheneas, who prophesied that the apocalypse would begin in 1925. After 1925, Doyle began a new journal of spirit communications that was published in 1927 as Pheneas Speaks. This later work contained weather predictions that were not mentioned in the original séance transcripts, suggesting Doyle added them after the fact and presented them as confirmed predictions. However, as interesting as these threads might be to scholars of new religions, they are of little importance to McCuskey, whose aim is to dissect rhetorical and epistemological claims.In many ways, this book seems more relevant to understanding contemporary culture wars than nineteenth-century Spiritualism. McCuskey’s study of Holmes is helpful for thinking about how, for example, many people feel confident that the CDC is not a good source of information about a pandemic but also believe that a drug used to de-worm livestock can cure COVID-19. The problem of confusing critical thinking with confirmation bias is also a serious one on college campuses. This book could be a useful entrée for exploring this problem in an undergraduate English seminar. It could also be a good choice for an upper-level religion and science course, assuming the students were at least somewhat familiar with the Holmes stories.