You're no fool. All your life you've heard tales of Scorpion Swamp and how it is criss-crossed with treacherous paths leading to the haunts of its disgusting denizens. One step out of place spells a certain and lingering death. But now, the swamp holds out the lure of treasure and glory -- and you cannot resist the challenge!
Puffin: #8 1984
Interestingly enough, the first book in the series that wasn't written by Steve Jackson (UK) or Ian Livingstone was penned by another Steve Jackson (USA).