From the introduction:
The universe of Rêve: the Dream Ouroboros is in the genre of heroic fantasy, also known as medieval fantasy. It is the imaginary universe of old legends, fairy tales, and sagas, of The King of Elfland’s Daughter and Mistress of Mistresses. Here there are kingdoms which border on the Unknown; vast, impenetrable forests, wastes inhabited by monsters; fortified cities crawling with a motley assortment of starving adventurers, fat burghers, mendicants, buskers, thieves, and guards; smoke-filled taverns where dice clatter on beer-stained tables; ancient, decrepit towers inhabited by magicians. In this teeming, baroque world intrigues are knotted and unraveled: there are duels, chases, sword fights, quests, curses, treasures...
Historically speaking, heroic fantasy universes never existed, and their geographies only exist in the imaginations of their authors. Witness Tolkien’s Middle Earth, Jack Vance’s Dying Earth, Leiber’s Lankhmar, Ursula Le Guin’s Earthsea... the list goes on and on.
Such is the ambiance of the universe of Rêve, the kind of places one expects to visit there, the kind of creatures one expects to meet there, the kind of adventures one expects to live there.
Heroic fantasy worlds usually are based on a legend, a cosmology which legitimizes their existence and lays their foundations. The foundation of the universe of Rêve, that on which everything rests, naturally is dream. The world is dreamed in the literal sense of the word. But the essential thing to grasp is the point of view; or, in cinematic terms, where is the camera? The point of view in Rêve is not that of the dreamer, but that of the dream itself, or more precisely, that of the creatures being dreamed. The dream is always and solely perceived from within itself. Any justifications which might be conjectured are only pertinent from this point of view. From the outside, what is there really? Giant reptiles snoring in their caverns, digesting their last meal before setting off to hunt their next one? Lords of light curled up beneath sumptuous canopies? Players rattling ten-sided dice? Whichever version you choose, none are of any interest whatsoever to the characters in the dream. They have no concern for the ‘where’ of the dreamers. This dream is their natural world. They fall asleep in it and wake up in it daily, even dream in it themselves. In this dream they are born, grow up, live, journey, suffer, and die. And for all that it does not seem to them to be a dream: it is physical, it is tangible, it is life. It is their world and they know nothing else.
Sometimes their philosophers say, “The world is but a dream of Dragons...” And most people react like one typically does to a philosopher: laughing, mocking, saying, “How could the world be but a dream? Isn’t the ground solid, the sun warm, isn’t bread nourishing, wine comforting? And none of that is real? You can’t be serious!” Just as in our real world, the characters of Rêve are far from all being mystics. Only a minority—intellectuals, philosophers, High Dreamers—having analyzed their own dream experiences and compared them to their world’s reality, have come to this conclusion. And this conclusion is the only one which is consistent with magic. Journeyers generally are part of this minority, given their own exposure to rifts in the dreaming and other oneiric experiences; they have had their eyes opened.