From the back of the book:
The Battle Below
Once, long ago, there was peace. The dwarves of Burok Torn and the dark elves of Dier Drendal fought together against the titanspawn and engaged in mutually beneficial trade. Yet war and betrayal tore these two races apart, and today Burok Torn is a place of sorrow, where the sins of the past trouble the rulers of the present, and the demands of honor drive elf and dwarf toward tragedy. Forced to fight a desperate war to save their wounded god, the dark eves assault the dwarves in a seemingly endless cycle of violence.
Burok Torn: City Under Siege details one of the greatest wonders of the age - the ancient dwarven city of Burok Torn, where rune magic and faith combine to create an indomitable realm. This book also provides information of the mysterioius city of the dark elves, Dier Drendal, and the events that have led the dark elves to make war on their dwarven neighbors. The secrets of the dwarven rune masters are also revealed, along with rules for playing this and several other powerful prestige classes. Game masters in any campaign will find a wealth of information in this book, and players will find endless challenges in the labyrinthine tunnels of Burok Torn and Dier Drendal