Exile (TSR Fantasy) by R.A. Salvatore

Hostile in ways that a surface-dweller could never know, the tunnel-mazes of the Underdark challenge all who tread there. Among these souls are Drizzt Do'Urden and his magical cat, Guenhwyvar.

Exiled from his drow homeland, Drizzt must fight for a new home in the boundless labyrinth. Meanwhile, he must watch for signs of pursuit - for the dark elves are not a forgiving race.