[ericthered]

Ideally, its a framework, not a setting, and not a setting builder book.

For reference, look at Horror, Monster Hunters, and Madness Dossier.

Madness Dossier is a setting. It gets into the nitty gritty of history and organizations. It only does one setting and possibly some closely related. I've never played a madness Dossier setting.

Horror is a setting builder book. Its full of great advice on how to build monsters and run horror games. But it requires a lot of work to get started. It can do "Any" horror setting, and as a consequence it does none of them quickly. I've used Horror, but I've never sat down and used the book to build a campaign. I've borrowed tools from it occasionally.

Monster Hunters is a framework. It has all the pieces of a setting, but it leaves out the history, the organizations, and the locations. It puts in the character templates, a mostly complete set of monsters, and assumed magic systems. You can build a Monster Hunters setting in 15 minutes (though I usually take a bit longer). And it will feel like its own setting, different from another monster hunters setting. I've sat down said "I'm going to run a monster hunters game", and then did so.

One of my favorite sections of Monster Hunters is "A Dark Reflection", where it instructs you how to build your campaign and setting. If a space opera set doesn't have that, I will be sorely disappointed.