From the introduction:
Shakhàn is set in the cold northern regions of the imaginary world of Telostic, a world in which many of those things known to be fables in the "real" world such as magic, supernatural monsters, deities, enchanted swords and the like really do exist. The setting of the Shakhàn game environment is largely pre-industrial – that is, the level of most Telostician societies is equivalent to those on Earth just after the collapse of the Roman Empire – but there are hints of earlier, greater civilisations with a much more highly developed level of technology.
The Introduction / Game Setting book provides a somewhat short overview of the game system and setting. The material presented is covered in greater detail a second time in subsequent volumes.