This is a well-done but incomplete product. As other reviewers have noted, it's very much done in the spirit of Star Frontiers, except that the game mechanics of FrontierSpace are much better - smooth, consistent, and pretty fast. The downside is that the book is quite incomplete - combat rules, for example, are in the Gamemaster's Guide, and although there are a selection of stock NPCs, there isn't a bestiary of aliens (other than alien PC races), monsters, and such. For that, you need the Gamemaster's Guide (which has a tiny selection of creatures along with good rules for crafting them). As such, there's a fair amount of prep-work from a GM, since you'll have to create adversaries from scratch continuously. I recommend the game, but be aware that what you're buying is not complete. If you're used to having to buy multiple books (like D&D), this won't be a major issue for you.