“Distributed revision control with Mercurial”, by Bryan O'Sullivan, is a freely licensed book about the Mercurial revision control system.
Home page: http://hgbook.red-bean.com/
The [http://hgbook.red-bean.com/hgbook.html HTML version] is split into one web page per chapter.
The [http://hgbook.red-bean.com/hgbook.pdf PDF version] is a single 1.3 megabyte file.
The [http://hg.serpentine.com/mercurial/book source code] is available to the adventurous.
Translations
[http://devnull.li/libromercurial/index.es.html Spanish] ([http://mercurial.intuxication.org/hg/mercurial_book_es/ source])
See also: [:BuildingMercurialBook]