An excellent offering of old-school sci-fi role-playing rules similar to Classic Traveller. Cepheus presents clearly-written rules in classic flavor for everything from generating a new character in a few minutes, to building an interstellar starship, to generating a sector of space for the players to explore. Best of all, the rules are 100% OGL, so you can use this as a basis for third-party material or even repack the rules and republish them as your own variant.
In other words, the Swords & Wizardry of Traveller.
[5 of 5 Stars!]