As the paperless future approaches, certain sorts of publications have inevitably moved into the all-digital realm faster than others. Most of us still prefer paper when it comes to beach novels, for instance, or the cherished volumes of our personal libraries. At the other extreme, scientific journals effectively went all-digital years ago, and thanks to GPS, maps and road atlases are quickly following. Last week saw another milestone: the symbolic funeral of paper encyclopedias, with the inevitable announcement that the Encyclopedia Britannica is ceasing print publication.

Encyclopedias, along with other reference works, would seem particularly obvious candidates for digitization. Paper encyclopedias are large, heavy, and expensive ($1,395 for the final print edition of Britannica). They are nowhere near as easily and thoroughly searchable as their digital counterparts. They cannot be easily updated, still less constantly updated. And they are far more limited in size. The 2002 Britannica contained 65,000 articles and 44 million words. Wikipedia currently contains close to four million articles and over two billion words (this information comes, of course, from Wikipedia).

Yet with the disappearance of paper encyclopedias, a part of the Western intellectual tradition is disappearing as well. I am not speaking of the idea of impartial, objective, and meticulously accurate reference. There is no reason this cannot be duplicated in digital media. Even Wikipedia, despite its amateur, volunteer authors, has emerged as an increasingly important and accurate reference tool, reaping respectful commentary last month from no less an authority than William Cronon, president of the American Historical Association. And I am not speaking of the pleasures that come from the serendipitous browsing of handsome encyclopedia volumes, in which the idle flip of a finger takes one from Macaroni to Douglas MacArthur, and thence to Macao, Macbeth, and the Maccabees. The internet provides its own opportunities for serendipitous discovery.

But the great paper encyclopedias of the past had other, grander ambitions: They aspired to provide an overview of all human knowledge, and, still more boldly, to put that knowledge into a coherent, logical order. Even if they mostly organized their articles alphabetically, they also sought ways to link the material together thematically—all of it. In 1974, for instance, the editors of the Encyclopedia Britannica added to the work a one-volume “Propaedia,” which sought to provide a detailed outline of human knowledge, while referencing the appropriate articles of the encyclopedia itself. Large headings such as “Life,” “Society,” and “Religion” were subdivided into forty-odd “divisions” and then further into hundreds of individual “sections.”

The single greatest and most ambitious such attempt to order knowledge, however, appeared more than two hundred years earlier: the legendary French Encyclopédie edited by Denis Diderot and Jean le Rond d’Alembert (it initially appeared in 32 huge folio volumes, and is now available online in French in its entirety, and partially in English through an ongoing collaborative translation project). It was not the first encyclopedia. Predecessors date from even before the invention of printing, and proliferated during the Renaissance, as Harvard historian Ann Blair has recently shown. Like present-day encyclopedias, Diderot and d’Alembert’s used alphabetical organization. But as d’Alembert himself explained, in a “Preliminary Discourse” to the work that became one of the key philosophical texts of the Enlightenment, it also aimed “to set forth … the order and connection of the parts of human knowledge.” It did so in several ways: through the “Preliminary Discourse” itself; through a visual “Map of the System of Human Knowledge”; and through a careful system of cross-references between articles. Diderot himself grandly claimed that the work contained all the knowledge necessary to save mankind from a new dark ages (“What gratitude the next generation following such troubled times would feel for the men who had … taken measures against their ravages by protecting the knowledge of centuries past!”).