In 2000 the RAND Corporation invited a group of historians—including me—to address a newly pressing question: Would digital media revolutionize society as profoundly as Gutenberg and movable type? Two decades later, John Thompson’s answer is yes, but not entirely as predicted. And our forecasts were often wrong because we overlooked key variables: We cannot understand the impact of technologies “without taking account of the complex social processes in which these technologies were embedded and of which they were part.”

Mr. Thompson provides that context in “Book Wars,” an expert diagnosis of publishers and publishing, robustly illustrated with charts, graphs, tables, statistics and case studies. An emeritus professor at Cambridge University, Mr. Thompson published an earlier dissection of that industry, “Merchants of Culture,” in 2010, but now he finds that capitalist landscape radically transformed.

Not long ago everyone thought (or feared) that ebooks would sweep the ink-and-paper book into the recycle bin of history. But they peaked in 2014 at just under 25% of U.S. book sales, then settled back to about 15% in the U.S. and roughly 5% in Western Europe. It turned out that the printed book had unique advantages (easy to navigate, no power source needed, works even if you drop it on the floor). Another consideration is that bookshelves stocked with physical books serve the essential purpose of advertising our literary tastes to visitors. And far from devastating the publishing industry, ebooks boosted their profits even as their revenues remained more or less flat. (Compared to printed books, they are cheaper to produce and distribute, and they don’t burden publishers with warehousing and returns.)

For anyone bewildered by the transformation of the book world, Mr. Thompson offers a pointed, thorough and business-literate survey. He tracks the arcane legal battles surrounding the creation of Google Books, and explains why the Justice Department filed an antitrust suit against Apple and the Big Five publishers, but not (so far) against Amazon. He rightly regrets the shrinkage of newspaper book reviewing: the first decade of the 21st century saw newspapers from Boston to San Diego pull back on book reviews. That said, Mr. Thompson could have devoted more attention to the rise of reader-written online literary criticism, a populist substitute for the Lionel Trillings and F.R. Leavises of the past.

In spite of worries that small independent booksellers would disappear, they are still with us. But they were challenged in the 1960s by the shopping-mall chains of B. Dalton and Waldenbooks, which were superseded by Barnes & Noble and Borders superstores. These in turn were eclipsed by Amazon (founded 1994), triumphing largely because it sold all books to everyone, everywhere. Though we romanticize corner bookstores, they were numerous only in the largest metropolitan centers. In 1928, a city like Cincinnati had seven bookshops. Small-town America bought books at department stores, at pharmacies, or nowhere.

Mr. Thompson insists that “the turbulence generated by the unfolding of the digital revolution in publishing was unprecedented. . . . Suddenly, the very foundations of an industry that had existed for more than 500 years were being called into question as never before.” I would be careful with the word “unprecedented.” Print-on-demand has been with us for some time: the Chinese did it for centuries with woodblocks. The modish practice of crowdsourcing to finance books has a precursor in 18th-century subscription publishing, as readers pledged in advance to buy a forthcoming book. Amazon today dominates bookselling, but Mudie’s Lending Library enjoyed an equally commanding position in Victorian Britain, and raised in its day serious concerns about corporate censorship. (Mudie’s puritanical acquisitions policies meant that novelists like George Meredith were penalized for honest treatment of sex.)

In fact, the 19th century witnessed a transformation of the book business as dizzying as our own: New reproduction technologies dramatically drove down the price of books and increased print runs by orders of magnitude, creating for the first time a global literary mass market, bringing Walter Scott to Japan and Harriet Beecher Stowe to Russia. Today, the absorption of family-owned publishers by conglomerates has raised questions about whether there is still a home for literary and controversial authors with limited popular appeal, but that change was complete before the full impact of digital media. If you’re worried about media concentration (and you should be), the fact remains that all the great Victorian novelists were published by a half-dozen London firms. The desktop computer has vastly expanded opportunities for self-publishers, but there were plenty of them in the past: think of Martin Luther, Walt Whitman, Leonard and Virginia Woolf or countless job-printed village poets and memoirists.

My warning to the RAND corporation was to avoid succumbing to the “Two Big Bangs Theory”—the assumption that there were only two world-changing events in the history of print, in or around 1450 and 2000. With books, change is a constant. In the last two centuries the publishing trade has dealt with one creatively destructive innovation after another—mechanized printing and papermaking, railway bookstalls and distribution networks, linotype and offset printing, photomechanical reproduction, paperbacking and books-of-the-month. The movies opened up vast new possibilities (and revenues) for novelists, who increasingly wrote with the screen in mind, as Ernest Hemingway did when he insisted on casting Gary Cooper in “For Whom the Bell Tolls.” And television supercharged book publicity, climaxing (so far) with Oprah. While Mr. Thompson is entirely right to conclude that the transformation of publishing in the past 20 years has been bewildering, that’s nothing new. In a dynamic capitalist economy, the dust never settles.

Mr. Rose’s “The Intellectual Life of the British Working Classes” has recently been published in a 20th-anniversary edition by Yale University Press.