My D&D campaign uses a mix of published and self-made adventures, including hybrids where for example I made my own 4E version of the classic Ravenloft adventure. So what is "an adventure" before it is actually being played in D&D? It is a collection of basically two sorts of data for the dungeon master: One dealing with technical stuff like the monsters and treasures of an encounter, and the other dealing with descriptive and background information: What is the history of the place? What are the motivations of the NPCs? How does the place look?

As I shortly mentioned yesterday, one part of the descriptive information is the boxed text of D&D adventure modules. It describes what the players see of for example a room when they enter it and is supposed to read aloud by the DM to the players. It also can contain the start of dialogue, for example when the players get somewhere and are greeted by an NPC. I have two major problems with boxed text: First of all the quality of it isn't always all that great, and reading text aloud usually makes the text sound even worse. And second my source material tends to be in English, while I play my campaign in French, with several players who don't speak English well or at all. So I'm forced to paraphrase the boxed text in my own words in a different language, which might either improve or decrease the quality of it. But that is still the easier part of handling information.

The more difficult part is handling all sorts of background information: The haunted wizard tower was built by the wizard Alonso 200 years ago and is deserted since one of his summoning spells went wrong. Okay, and now what do you do with this information? Tell it to players as a voice from the off? Engrave it on a plaque at the entrance to the tower? I don't think so!

So one method I found helpful in preparing adventures is to list all the tidbits of information, secrets, and rumors in a table, and add a column to that table with the heading of "who knows?". By identifying who knows a bit of information, it becomes obvious on how the players can find out about it. The "who" doesn't have to be a person, for example the wizard Alonso might have left a diary in his tower. Or the information about the construction of the tower might be found in history books.

Some of the information will require that the players actively look for it, for example if they are being sent to the tower to retrieve some artifact they could start asking what they can find out about the tower by visiting a local sage or library. Other information comes in the form of clues during the adventure: The broken summoning circle at the top of the tower with the crushed skeleton of Alonso in the corner of the room. Rumors in the tavern about the locals not going to the tower because it is haunted. But the idea is always to have a possibility for the players to find out or piece together the information written in the adventure module.

There is no use for a page full of the history of an NPC and his motivations if that history and motivation doesn't have any visible impact on the adventure. What you don't want is players opening a random door in the dungeon to find themselves in a boss fight with an arch-villain they never heard of before, with the villain dying without the players ever finding out what the heck the guy did down there. Unfortunately some published adventures have encounters like that. So making that table of information and who knows about it will at least reveal the flaw of the adventure, and allow the DM to fix that by adding more clues.

One final thing to consider after having compiled the table of who knows what information is thinking about whether the quantity of information is appropriate for your specific campaign. For example my group only plays about twice per month, and that limits the amount of information I can give out verbally and be sure they still remember three sessions later. That is why for example I make handouts for quests, so that the players don't ask in the middle of the dungeon "why are we here again?". On the other extreme I'd also be worried if my list of information about the adventure was too short, because that would suggest that there isn't enough story and opportunity for role-playing. In any case, having a "who knows?" table of information is helpful.