Part roleplaying game, part skirmish battle game, all mayhem. See that Crimson Fist in the middle? Yes, he is smiting his enemies with the head of one of their own. This game was METAL. It is the tail end of the Oldhammer phase of the game before launching into the Middlehammer of big boxes and mass armies.
"In the nightmare future of the fortieth millenia, only the superior psychic ability of the Emperor shields humanity from certain extinction. Dedicated to his service are the warriors, agents and myriad servants of the Imperium. Foremost amongst them stand the Space Marines, men strengthened by advanced bio-processing techniques to create the ultimate human warrior." -back cover
Many of the tropes that are present in fifth edition 40k were seeded all the way back in 1987, such as Genestealers (orignally from one of the moons of Ymgarl and seperate from Tyranids), Orks, and even Dark Eldar. Some things, of course, have fallen by the wayside (alas, poor Squats).
"There is no time for Peace
No respite, No forgiveness.
There is only WAR." -back cover
Publication information:
Priestley, Rick. Warhammer 40,000: Rogue Trader. Nottingham: Games Workshop, 1987. 272 pp (plus counters and templates).