This is the classification system that the United States Library of Congress uses. This is for my own reference and the subcategories listed here are the ones I'm interested in.
A - General Works
B - Philosophy, Psychology, Religion
G - Geography, Anthropology, Recreation
H - Social Sciences
N - Fine Arts
NK - Decorative Arts
This category includes what I would call "craft": ceramics, glass, metalworking, woodworking, textiles, etc.
P - Language, Literature
Q - Science
QA - Mathematics and Computer Science
Programming in general is categorized here too, which I don't really agree with. Sure, finite automata and Turing machines can go in QA, but are they really the same category as essays on software development?