Adventure and Intrigue with a Proud Warrior Race
From the back of the book:
Spinward of the Imperium, a race of ferocious carnivores has evolved to intelligence and rules hundreds of star systems. They are the Aslan, interstellar neighbors of the Imperium. This warrior race has long been a mystery to the ordinary human, and now it is possible to learn more about their culture and society.
Aslan, Traveller Alien Module 1, describes in detail this alien race, its homeworld, and its starfaring society.