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Dewey’s Decimal Deception

March 2023
1min read

The “American Character” in last December’s issue was MeIvil Dewey, the librarian who became famous as the father of the Dewey decimal system. The historian John Maass read the article and responded by sending us one of his own, which appeared in 1972 in the Wilson Library Bulletin —and which claims that Dewey cribbed his great idea.

The real inventor, says Maass, was William Phipps Blake, a nineteenth-century Renaissance man who was chosen to classify the exhibits at the 1876 Centennial Exhibition. In May of 1872—a full year before Dewey pre-ented his system to the library committee of Amherst College—Blake turned in his outline to the Centennial Commission. “We propose,” it read, “ten comprehensive divisions, to be named Departments. … We propose to subdivide each of these Departments into ten Groups, and each Group into ten Classes.…” The system was almost identical to Dewey’s. Could the young librarian have seen it? Certainly, says Maass. In February of 1873 leaflets describing Blake’s system were sent to colleges throughout the country, and one could have ended up in the Amherst library.

Dewey changed the names of Blake’s divisions to Classes-Divisions-Sections. “Blake’s and Dewey’s Classes,” writes Maass, “were, of course, not the same. The former classified the products of one temporary exhibition; the latter tried to encompass all human knowledge in a permanent library classification.” Nonetheless, many of the categories are remarkably similar. Here is one of Blake’s from 1873:


940 Landscape

941 Architectural

942 Portrait

943 Albertype, Woodburytypes, Heliotypes, etc.

944 Reproductions

And here is Dewey’s 1876 counterpart:


771 Materials

772 Ambrotype and Daguerreotype

773 Photograph

774 Heliotype, Albertype, etc.

775 Photolithography

777 Portrait

778 Landscape

“Melvil Dewey,” Maass concludes, “deserves great credit for … adapting Blake’s system … [but his] deliberate failure to ever acknowledge his large debt to William Phipps Blake is another matter.”

Maass’s 1972 article has been widely reprinted and summarized, but the pro-Dewey forces have not responded. “I later heard,” writes Maass, “that the board of the Dewey Decimal Classification (including Dewey’s son) had constituted themselves as a committee to refute my article. They called no witnesses and decided not to take any official notice of the article because I had presented ‘no proof.’ Actually, both the Wilson Library Bulletin and the Library of Congress demanded proof, and they were satisfied by the dozens of documents I sent them.”

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