There are those players and DMs who thrive on realism and ingenious integration within their games, and then there are those of us who have to slap campaigns together in 10 or 15 minutes. Adam's Balduran's Guide to Kingdom Building is one of the most useful supplements you could ever ask for - it has monsters, maps, guidelines, tables, and all sorts of mechanics for ensuring that you can build the most comprehensive and realistic kingdom in your game.
The biggest strength of this product is the heavy importance of geographic location and biome in which your kingdom is located, as this is going to play directly into how your kingdom is going to function - an arctic kingdom is going to be scores different in the way it is built and managed than a marsh or plains kingdom. If you partnered this with Neverember's Guide to Urbanization, you would be set to create and flesh out entire worlds for life. In 160+ pages you get so much amazing new content that it is unreal.
This is a stunning example of content creation perfection - really everyone who can should take a look at and buy Balduran's: you will not be disappointed in the slightest.
Comics, Clerics, & Controllers d20: Nat 20
[5 of 5 Stars!]