The Dewey Decimal Classification is supposedly the most widely used library classification system in the world. It dates from 1876, with the most recent revision in 2004. While most academic (college and university) libraries use the Library of Congress Classification, the DDC is used in virtually all U.S. public library systems and primary/secondary school libraries. In other words, it’s how we first learn the world of knowledge is organized, and at least half the population never learns anything else.

Here’s how the DDC organizes religion:

200 Religion
210 Philosophy and theory of religion
220 The Bible
230 Christianity and Christian theology
240 Christian practice and observance
250 Christian pastoral practice and religious orders
260 Christian organization, social work, and worship
270 History of Christianity
280 Christian denominations
290 Other religions

So perhaps it’s not entirely surprising that we as a society have such a warped view of the religious landscape. (”Other religions” covers two-thirds of the world population, in case you were wondering.)

UPDATED: Apparently at least one person felt like this was a personal attack of some sort. I don’t see how there’s any way to read that into what I wrote, but just to be clear: my (only) point here is that the US “standard” system for categorizing library books presents an inaccurate view of the relative size of Christianity with respect to other religions.