A Spell and the ability to use one forms an intricate part of the Fighting Fantasy world, being found in almost every region and being used for almost every purpose imaginable.
The Citadel of Chaos, The Riddling Reaver and Fighting Fantasy - The Introductory Role-Playing Game used a magic score which equated to the number of spells that could be cast during the adventure, often with the player selecting a limited array of spells beforehand; whilst Scorpion Swamp was unique in the use of Spell Gems, each of which contained a certain spell and could be used once.
The Advanced Fighting Fantasy trilogy and the Sorcery! series introduced a different kind, in which casting spells required the expenditure of stamina - and sometimes a specific item, although this was considerably more accentuated in the Sorcery! series - in order to work. Similar stamina-draining spells were found in Temple of Terror, with the notable exception of Create Water.
Although these books allowed the player to cast spells of their own, it is far more common that spells are actively cast against them or passively attempt to affect them. These are even more varied, ranging from an agonising torture spell known to Zharradan Marr to a spell of imprisonment in the Trial of Champions to random teleportation magic in Fighting Fantasy - The Introductory Role-Playing Game.