The Citadel of Chaos (Puffin 2, Ian Miller cover), paperback Fighting Fantasy gamebook, by Steve Jackson
“Who knows what monstrous creatures lie in wait in the Citadel of Chaos?
The Citadel holds a dark and dangerous peril for anyone foolhardy enough to venture through its gruesome gates. And yet venture you must, for your mission lies at the heart of the Citadel, with the dread sorcerer, Balthus Dire!
Two dice, a pencil and an eraser are all you need to make your journey. YOU decide which route to take, which monsters to fight, and where to use your special knowledge of the magic arts.”
The adventure sheet is unused but a previous owner has written his name inside the front cover. Note that this is the rarer 1987 printing with the Ian Miller cover.