Fighting Fantasy: Forest of Doom by Ian Livingstone
PART STORY, PART GAME - PURE ADVENTURE! Are YOU brave enough to face the foes and fiends of this nightmare forest.? A war is raging and your help is needed to vanquish the evil trolls. To save the dwarfs, you must find the grand wizard Yaztromo and track down the pieces of a legendary war hammer lost in the depths of Darkwood Forest where gruesome monsters lurk . Step up, hero, it's time to fight!