We started the Dewey Decimal Cataloguing system last night.

I have written an (unpublished) YA fantasy novel set in vast library. The library in the book takes the form of a fractal bookcase: a bookcase made up of bookcases made up of bookcases.

The structure was inspired by the Dewey Decimal system: if you look closely, you can just see that each Shelf corresponds to a main Class in DDC. The Rows are Divisions, and the Towers are Sections.

It was a cute concept, even if my diagram doesn’t quite do it justice.

What I discovered last night though, as we dutifully clicked our way through WebDewey to practice our cataloguing skills, was that Dewey is less of a bookcase and more of a maze.

Which is to say: when you are at your destination and have the Dewey Decimal number for a work in front of you, it’s easy to work backwards and understand the rightness of why the work sits there.

But working from the outside in–starting with a text, and then trying to navigate through the Classes and Divisions and Sections to find the correct number–is an exercise in dead-ends and doubling back.

Consider, for example, Jim Henson’s Labyrinth. What number do we assign to this movie?

The main class is clearly 700 – Arts & Recreation.

The division also seems clear: 770 – Photography, computer art, film, video. But which section should we move into?

• 700 – Arts & Recreation
  • 770 – Photography, computer art, film, video
    • 770 – Photography, computer art, cinematography, videography
    • 771 – *Techniques, procedures, apparatus, equipment, materials
    • 772-774 – Special photographic processes
    • [775] – [Unassigned]
    • 776 – Computer art (Digital art)
    • 777 – Cinematography and videography
    • 778 – Specific fields and special kinds of photography
    • 779 – Photographic images

Presumably 770, right?

• 700 – Arts & Recreation
  • 770 -Photography, computer art, cinematography, videography
    • 770.1 – Philosophy and theory
    • 770.2 – Miscellany
    • 770.5 – Photography–serials
    • 770.74 – Photography–museums
    • 770.9 – History, geographical treatment, biography

And there it is: that feeling of being lost, of wandering into a dark dead end, where the wind howls and there may be wolves.

Backtrack. Try again. Explore other corridors, other paths. I didn’t spend my teens playing Dungeons & Dragons for nothing.

Or I can just google it.

This post on 025.431: The Dewey blog says the correct number is 791.43. Playing around with WebDewey, the right path through the Dewey maze is:

• 700 – Arts & recreation
  • 790 – Sports, games & entertainment
    • 791 – Public performances
      • 791.4 – Motion pictures, radio, television
        • 791.43 – Motion pictures

It makes sense looking backwards, right? You can understand how Motion pictures fits under Motion pictures, radio, television, which fits under Public performances, which fits under Sports, games & entertainment, and so on.

There’s no way in hell I would have made the connection going the other way though. I would have hesitated at Sports, games & entertainment, and would have turned back at Public performances.

So this is my first impression of the Dewey Decimal Cataloguing system: a maze that can only be solved by walking it backwards.

Borges would be delighted.