Games Workshop reprinted the original edition of Warhammer 40,000 for the tabletop wargame's 30th anniversary back in 2017, but only made it available at Warhammer World in Nottingham. If you weren't able to pop over to the Midlands to secure a copy for yourself, you're about to get another chance.
At the bottom of a recent preview of new releases, Games Workshop announced that a reprinted first edition Warhammer 40,000: Rogue Trader rulebook will be available via print-on-demand, and orders can be placed between October 14 and October 23. Copies will be mailed out "within 180 days of the ordering window closing", though a price has yet to be announced.
The first version of Warhammer 40,000 came out in 1987, and in some ways was quite different to the current 10th edition. For starters, it was as much a roleplaying game as a wargame, with the assumption that a third player would take the part of a "gamesmaster" who interpreted the rules, presented the scenario, and took the part of any independent forces on the battlefield. Battles were at a squad level, with substantially smaller armies, and an assumption you'd use tokens or whatever miniatures were at hand since so few official minis existed at that point.
The setting was different as well, with the word "primarch" referring to highly ranked space marines rather than demigods and Chaos going unnamed until supplements started coming out. The tone, however, was right there from the start in opening text that described the Imperium as "the cruellest and most bloody regime imaginable" and the time as "a dark and terrible era where you will find little comfort or hope."
A tabletop RPG also called Warhammer 40,000: Rogue Trader came out in 2009, and it's the latter that Owlcat is basing its CRPG on, which is currently scheduled for release on December 7.