The following is text from "Vampire: The Masquerade", third edition (copyright 2000). This is selected text which reveals the authors' view of what roleplaying is and the responsibilities of GM and players.
Introduction Chapter, page 21
The book you hold is the core rulebook of Vampire: The Masquerade, a storytelling game from White Wolf Publishing. With the rules in this book, you and your friends can take the roles of vampires and tell stories about the characters' triumphs, failures, dark deeds, and glimmerings of goodness.
In a storytelling game, players create characters using the rules in this book, then take those characters through dramas and adventures, called (appropriately enough) stories. Stories are told through a combination of the wishes of the players and the directives of the Storyteller (see below).
In a lot of ways, storytelling resembles games such as How to Host a Murder. Each player takes the role of a character -- in this case, a vampire -- and engages in a form of improvisational theatre, saying what the vampire would say and describing what the vampire would do. Most of this process is freeform -- players can have their characters say or do whatever they like, so long as the dialogue or actions are consistent with the character's personality and abilities. However, certain actions are best adjudicated through the use of dice and the rules presented in this book.
Whenever rules and story conflict, the story wins. Use the rules only as much -- or preferably as little -- as you need to tell the thrilling stories of terror, actions, and romance.
Vampire is best played with a group, or troupe, of two to six participants. Most of these people are to be players. They create vampire characters -- imaginary protagonists similar to those found in novels, cinema, and comics. In each troupe, however, one person must take the role of the Storyteller. The Storyteller does not create one primary character for herself. Rather, she acts as a combination of director, moderator, narrator and referee. The Storyteller invents the drama through which the players direct their characters, creating plots and conflicts from her imagination. The Storyteller also takes the roles of supporting cast -- allies with whom the characters interact and antagonists against whom the characters fight. The Storyteller invents the salient details of the story setting -- the bars, nightclubs, businesses and other institutions the characters frequent. The players decide how their characters react to the situations of the game, but it is the Storyteller (with the help of the rules) who decides if the characters actually succeed in their endeavors and, if so, how well. Ultimately, the Storyteller is the final authority on the events that take place in the game.
Storytelling Chapter, page 254
Forget about the pages of rules and the handfuls of dice. Close the book, turn out the lights, and tell me a story about dark desires and relentless hunger. I'll tell you about a vampire, about her talents and her weaknesses, and you tell me what kind of challenges she faces, what rewards or perils come her way. You plan the twists and turns the story will take, and I will tell you how the vampire navigates them. Only you know how the story ultimately ends, but only I know how the vampire will arrive there. Along the way, the work you put into the story gives my vampire the chance to grow and develop, and her actions breathe life into the world you have created.
That is the challenge of storytelling. Vampire is about the inner struggle between humanity and monstrosity in the face of unfettered power and eternal life. No mortal law binds the Kindred, no moral code restrains them -- only fading passions or ideals nurtured in mortal life keep the vampire from indulging her horrific nature, and those memories become harder and harder to recall as the years stretch into centuries. In short, Vampire is about the characters and how they develop -- or wither -- in the face of tragedy and temptation. Can a mortal steeped in religious faith reconcile her deeply held beliefs with her lust for blood? Can a vampire resist the temptation to Embrace her lover rather than face an eternity of loneliness? The Beast awaits any Kindred who surrenders herself completely to her predatory urges. The Storyteller must draw on the characters' backgrounds, hopes, and ambitions to create stories that challenge their -- and their players' -- convictions and beliefs. As a result, taking on the role of a Storyteller in a Vampire game is very demanding, requiring careful thought and background work to build a world that is a nightmare reflection of our own, enticing and repellent, exhilirating and horrifying. You must evoke the thrill of inhuman power and a fear of what might happen if the character ever loses control. And you can't let the characters just keep to themselves and survive off daring thefts from the local blood bank. The night air is thick with the intrigues of the elders as Gehenna draws nigh, and the ancillae manipulate neonates as they see fit, promising great rewards -- and even greater risks.
Storytelling sounds like a lot to manage all at once, and it is at first. Fortunately, the Storyteller doesn't have to do it all at once. The secret to successful storytelling is, ironically, the work of the players. Fulfilling the expectations and interests of a chronicle's players is the first trick to creating the game's setting. Then -- if the chronicle and its overall story have been carefully developed -- the actions of the characters, both good and bad, will have consequences that in turn spawn further stories. Never forget: The more the players are involved with what happens in a chronicle, the less work you, the Storyteller, must take upon yourself. You aren't supposed to do it all alone. The Storyteller should have as much fun with the game as the players, and this chapter details how.