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.
Publications
From Reiser4 FS Wiki
Publications
- Reiser4 Transaction Design Document (Apr 05, 2002)
- Future Vision (Jan 25, 2001)
- Reiser4 Whitepaper (Nov 13, 2006)
- Three reasons why ReiserFS is great for you (2002)