Wikipedia:Offline Content Generator

The Offline content generator (OCG) was previously used to build books from collections of Wikipedia pages.

A group of pages could be selected to form a book in any of several formats, via the Book Creator which in turn used the OCG to convert the articles to the selected book format.

Withdrawal
OCG became unmaintainable and Wikipedia stopped using OCG in 2017, as part of a general withdrawal from all Wikimedia Foundation sites.

Page PDF creation does not use OCG and has remained available.

Replacement
The intention is to replace OCG with a new facility. The first two attempts at a replacement failed. As of May 2018, PediaPress have agreed to seek a solution.