Most of the documentation is a snapshot of the old Namesys site (archive.org, 2007-09-29).
There was also a Reiser4 Wiki (archive.org, 2007-07-06) once on pub.namesys.com.
Reiser4 development appears to have stalled and ReiserFS is deprecated and scheduled to be removed from mainline Linux in 2025.
Talk:Reiser4 Howto/GRUB
From Reiser4 FS Wiki
Yes, this howto is heavily based on this howto over here -- Chris goe 18:33, 3 July 2009 (UTC)