[bovermyer]

Some of this is economies of scale. It's fairly cheap per unit to print 1,000,000 copies of a book. It's much more expensive (again, per unit) to print 1,000 copies.

Books like Lord of the Rings which are guaranteed to sell a large number of copies are much less of a risk to print large numbers of than books like Concrete Mathematics. The publisher rolls that expectation into the retail price.

Additionally, all one-off production costs (like paying an artist for cover art) are rolled into that retail price also, with the expectation that X number of copies will sell over the "initial life" of the book.

That "initial life" is usually the first year of a book's publication.

[AJ007]

The Doom and Wolfenstein 3D Game Engine Black Book(s) were priced at cost, per the author. Print on demand full color is very expensive.