I'm sure it's been done in other games, but I first appreciated how it tied everything together in Warhammer Online. It's a central gameplay gimmick in a recent Nintendo DS game called Avalon Code. And now it's got a prominent place in Battleforge, the collectible-card game RTS from Electronic Arts.

I'm talking about tomes.

Not just a book interface. I'm sure you can find plenty of games that have you paging through virtual pages. But what these three games -- an MMO, an RPG, and an RTS, respectively -- have in common is the way they use a virtual tome to dynamically present ingame info, such as back story, statistics, achievements, and so forth. Use tabs along the sides of the pages, hyperlinked tables of contents, and bookmarks to quickly get where you need to go. Page numbers can be used to give a sense for how far you've come and how far you have to go. The numbers can motivate completionists to fill in missing sections.

Warhammer Online assembles pretty much every facet of the game in its "Tome of Knowledge". Here is recorded every creature you've met, every quest you've accomplished, and every place you've explored. It's a reference for gameplay mechanics and lore. And it's dynamic and constantly updated as you play.

Avalon Code is based on finishing a 1500-page "Book of Prophecy", which is constantly open on the lower screen on the Nintendo DS. You use the book to basically re-write reality, but it's also as a way of documenting your progress. Press flowers, study monsters, fill in maps, and so on to add pages. You can find legends for ingame icons, help files, and monster and weapon stats. There's even a memo section in the back where you can write with the stylus. I haven't gotten very far, but the virtual book is a great gimmick for moving the game forward. As you play, the story you're writing is quite literally laid open before you.

In Battleforge (pictured), the "Chronicle" is where you find your replays, your stats, and all the information about the game world. Many of the pages feature big fat padlocks, which all but dare you to play the game to find out what's behind them. You have to beat scenarios to unlock backstory and upgrade cards of particular mana types to unlock legends for that color. It's a shame they couldn't build their card collection concept into this book, which would have brought the whole thing full circle.

Note that you can't very well do this in any game. It wouldn't make much sense in, say, Eve Online or Peggle to have a giant book. But in these instances, the book interface is damn near perfect. Nothing says Ye Olde Fantasy World quite like a big fat tome.