The Europa Universalis 4 Wiki contains significant information about the workings of the game. It convers numerous topics; everything from basic game mechanics, to a Beginner's Guide, to information on modding.
It can be visited here.
Anyone can contribute to the wiki. If you want to become a contributor please register (though you can also edit anonymously), and check out the work needed page. If you spot anything in use of improvement, don't hesitate to make an edit.
Adding strategy guides to country pages is also fair game, just make sure to read the style guidelines first.
To converse with other wiki editors on the fly, feel free to join the IRC channel.
Here's a list of some of the more important pages:
- Beginner's guide
- Economy: Production • Tax • Tariffs
- Trade: Trade nodes • Trade goods
- Console commands
- National ideas • Unique national ideas
- Land warfare: Army • Land units
- Naval warfare: Navy • Naval units
- Government: Religion • Culture • Westernization
- Communities: Jargon