From the back of the book:
"Crouched within a vast cavern complex, the city of Sheoloth is a skeleton of stone wrapped in tortured flesh and clad in robes of woven silk. From its first beginnings as a captured fortress, Sheoloth has slowly expanded over the decades. Expansion of the city eats away at the stone around it, leaving behind thick cores of marble and basalt to support the ceiling of the city. Glittering corpselights wander the streets, providing illumination to both the estates of the nobility and the meanest hovel of the most poverty-stricken foreigners. It is a place of strange beauty and stark power, at once serene and filled with chaotic violence, Sheoloth is a true home to the drow.
This mighty tome details a complete subterranean city, populated by the most vicious and twisted race ever depicted in fantasy - the Drow! Adaptable to any existing campaign, Sheoloth may be used as the centrepiece to many scenarios, pitting the players against the most evil elves to rule the Underdeep, or as the scene of destructive politicking between rival drow nobles."