Minimalism and Maximalism (AKA 'do as thou wilt shall be the whole of the Lore').

The first game setting I ever read wasn't a D&D book: it was Titan, the 1986 world-book which described the setting of the then-popular Fighting Fantasy gamebooks. As anyone who had an interest in fantasy and/or gaming during the 1980s will probably remember, Fighting Fantasy was everywhere at the time. (In retrospect, they played an obvious transitional role between the early tabletop RPGs of the 1970s, which they grew out of, and the computer RPGs of the 1990s, which ultimately supplanted them.) Early on, each FF gamebook was completely independent, with only the barest hints of any kind of shared setting. But then Titan came along, and mapped out - literally - how Firetop Mountain and Scorpion Swamp and The Citadel of Chaos and The Forest of Doom all fitted together as component parts of a single imaginary world, with its own history and gods and mythology and all the other stuff you'd expect to find in a fantasy setting.

This map has held a special place in my heart ever since.

At almost exactly the same time, the same thing was happening to D&D. The Keep on the Borderlands and The Lost City and The Palace of the Silver Princess aren't really located anywhere in particular: they're just places where adventures can happen. But as time went on, the D&D adventure modules started getting welded together: first as part of something called 'the known world', and then as components of the Greyhawk and Mystara campaign settings. And then the deluge of setting information began.

I have always found this process rather fascinating. In 1994, the background of Warcraft consisted of little more than 'Orcs from orc-world are attacking humans from human-world! Now fight!' 23 years on, there's more Warcraft lore than you can shake a level 110 Blood Elf Death Knight at. Shortly before Magic: The Gathering went into production in 1993, Richard Garfield decided that just having cards called 'Dryads' or 'Dragon' or 'Warlord' sounded a bit bland, so he went through the list adding nonsense adjectives: Shanodin Dryads, Shivan Dragon, Keldon Warlord, and so on. 24 years later, there have been entire novel cycles written about the heroes of Keld and the histories of the Island of Shiv. In 2001, a couple of brothers from Cambridge coded a simple little online game called Runescape, where you could run around a fantasy village and do a few quests for the locals and fight goblins out in the woods. 16 years worth of weekly updates have turned this minimalist concept into a sprawling, baroque nightmare of false gods and dying worlds and hidden secrets. Let's not even get into what's happened to Warhammer 40,000 in the three decades since some innocent Games Workshop staff member first said: 'What if we did Warhammer, but, like, in space?'

Lore accumulates. It accumulates fast. A dungeon grows into a wilderness which grows into a campaign world. When I was 14, and I had just started a new AD&D campaign, I drew a circle in the middle of a piece of paper and said to the players: 'This is an inland sea. The dwarves live to the north-east and the elves live to the south-east and the humans live everywhere else.' By the time I was 18 I had written hundreds of pages of information on the geography and history and races and religions of the enormous fantasy world which now sprawled out in every direction from that original circle-on-a-map. To my shame, I think I can even still remember most of it. (Narsier. Utrean. Faserik. The Cathideni City-States. The Throongorm Mountains, whose foothills were home to the Blackfang goblin tribes. The Bloody Plains. The Men of the Keeps. The Forest of Whispering Trees.) The rise of the internet has made it very clear that the creation of immense imaginary worlds, complete with myths and legends and lineages of kings and whatnot, is not some rare and difficult achievement. Quite the contrary: it can be, and very often is, accomplished by anyone with a bit of spare time and a word processor.

How much lore is too much lore? Everyone has different tolerances. Some people will always prefer the most minimalistic, lightly-sketched-in version of a setting to anything that comes later: the 1977 version of Star Wars, the 1987 version of Warhammer 40,000, and so on. Others really love the sheer piling up of information for information's sake, preferring the most complex and fully-detailed versions precisely because of their detail and complexity. As far as RPGs go, though, I think the key point to bear in mind is probably that the low-lore and high-lore settings are different kinds of tools, which are useful for different kinds of games:

• A minimalist approach presents a setting as though from an outsider's perspective, in which only the most sailent characteristics of the situation are immediately obvious, and the reasons why things are the way they are is often unclear. It thus encourages PCs to act like outsiders, engaging in activities such as exploration, crime, raiding, and the disruption of established social orders and hierarchies.  
• A maximalist approach presents a setting as though from an insider's perspective, in which the complex web of relationships and institutions and traditions which bind different elements of the setting together are intimiately understood. It thus encourages PCs to act like insiders, engaging in activities such as trade, politics, or military service, which rely on all parties having a reciprocal understanding of their relationships with society as a whole. PCs in such settings are much more likely to join established groups and work within them, rather than just trying to rip them off or tear them down. 

A minimalist setting will feel open, mysterious, and full of possibilities, its history and geography a largely-blank canvas across which the PCs can paint their own crazy destinies. A highly-detailed setting, by contrast, will feel defined and bounded, with PCs much more likely to try to seek places for themselves within the limits defined by its existing social systems - even if it is exactly the same setting. You can describe a setting as vast and wide-open and full of mystery and adventure, but if you then go on to explain everything about it in encyclopedic detail then it will feel small and cramped and fussy, no matter how many thousand-mile wildernesses you draw on your map. (Exhibit A: the Forgotten Realms.) By the same token, even if your setting is described as crazily complex, it will feel as though it is open to freewheeling adventure as long as that complexity is communicated through broad-brush outlines and maybe a random table or two.

I've deliberately kept the level of detail and interconnectedness in ATWC very low, in order to encourage that outsider's perspective, and to ensure that everything feels suitably open. But if you wanted your PCs to feel like insiders to one part of the setting - their home khanate, for example - then one could easily detail that bit of the world in great thoroughness, presenting PCs with lists of clans for their characters to be from, famous warrior lineages they might be descended from, ancestor spirits whom they might revere, wrestling tournaments they might have taken part in, and so on. In fact, the contrast between their highly-detailed homeland and the lightly-sketched-in world outside - 'It's a city which trades in... um... goods and services? Anyway, there's lots of rich merchants about. Wanna rob one?' - might be quite a good way of emphasising the difference between their insider-perspective into their own culture, and their outsider-perspective on the huge and mysterious world outside. Their homeland is a place to live in. But the outside world is a place for adventure...