Darth Rivan's personal journals were a pair of books that contained the writings of the Sith Lord Darth Rivan. The journals came to be located within the bowels of Rivan's fortress on the planet of Almas and during the Clone Wars, the books were recovered from the fortress by a team of Jedi researchers. The researchers turned the tomes over to the Jedi Council, the governing body of the Jedi Order, and a section of the journals that detailed Rivan's thoughts on the Darkstaff, a powerful Sith artifact, was published on the HoloNet.
Sources[]
"The Darkstaff" (original article link) on Wizards.com (content now obsolete; backup link)