One of the first rules of Storytelling is "Show, don't Tell." Handing out ten pages of background material is definately the latter. Background is good, but the relevence needs to come out in game-play. There's nothing wrong with just feeding the players tidbits that their characters would know. Consider two approaches, telling and showing.
Telling - Before the game, the DM hands out a 20 page dossier on his world, detailing the politics, peoples, regions, customs, and power groups. His players, not knowing that D&D apparently involves homework, either don't read it or just skim it not understanding them. The DM is then frustrated when they don't know that the Knight of the Hawk that they met is sworn to defend the city of Evershine to the death when it clearly said so in the campaign guide.
Showing -
"As the knight approaches he confidently displays his crest marking him as a Knight of the Hawk. They are known for being both brave and stubborn, sworn to defend the city of Evershine with their lives"
Which of these is the better approach? Unless some bit of information about the world is relevent to what the PCs are doing, they really aren't going to care.