In Tunnels & Trolls, spell-casting ability is considered to be “psionic.” Warriors lack the ability. In the section called 'The Logic of Magic', an amusing typographical error reads: “Warriors can't spell cat. It's not a matter of stupidity.” Rogues and magic-users both possess the ability, but only magic-users have been trained in magic. With regard to rogues, the rulebook states, “while they can be taught individual...spells, [magic] never becomes second-nature to them. Rogues learn specifics when taught without really understanding the general framework for magic.”
Magic-User characters begin the game with all ten of the 'Level One' spells. Magic-users learn higher level spells from the wizards' guild, “which is a universal and quietly powerful organization throughout the...world.” The guild teaches new spells to magic-users at set prices based upon the level of the spell. A rogue can only learn spells from a magic-user willing to teach a spell to the rogue. This is done via the 'Level One' spell named 'teacher'. The rulebook informs us that “Magic-users are entirely justified in charging rogues whatever they can get for teaching them spells.” I do not see any prohibition – not even in later editions – against rogues learning the 'teacher' spell.
Unlike Dungeons & Dragons, a spell caster's experience level correlates the level of spell he or she is capable of casting; second level spell casters can cast second level spells, third level casters can cast third level spells, etc. In later editions, a character can learn spells greater than his or her level, but the wizards' guild does not permit spells to be taught except to magic-users of appropriate level. Otherwise, spells of a given level require the caster to possess a minimum amount of Intelligence and Dexterity. 'Level One' spells require an Intelligence of 10 (and later editions also require a Dexterity of 8). 'Level Two' spells require 12 Intelligence and 9 Dexterity; the wizards' guild charges magic-users 500 g.p. to learn one of these spells. 'Level Ten' spells cost 4,500 g.p. and require 28 Intelligence and 17 Dexterity. The attribute requirements may seem excessive; however, they are reasonable given the rate at which T&T characters increase their attributes.
Casting a spell also requires an expenditure of Strength; in effect, this turns T&T magic into a spell point system. The berserk rules and the rules for using weapons with less than required Strength also use the Strength attribute as a measure of endurance. The combat rules tell us that “Whenever a character's strength drops below 5 in combat, that person passes out.” Also, “If strength should ever be reduced to zero, you have burst your heart and killed yourself.” This does not bode well for non-human characters that start the game with limited Strength. In later editions, characters do not fall unconscious until they reach 1 Strength and any Strength loss beyond that point is applied to Constitution instead. Of course, in later editions, Strength is no longer used to power magic; a new attribute, Wizardry (or Power), has taken its place.
The Strength cost associated with spells can be reduced by using “magic staffs.” These 'staffs' reduce the Strength cost of each spell by a number of points equal to the magic-user's level, but the final cost is never less than 1. A standard magic staff costs 100 g.p., but any magic-user can make a makeshift staff that will burn-out after handling a number of Strength points equal to twice the magic-user's Intelligence. Lastly, there are deluxe staffs:
Deluxe staffs cost 500 gold pieces, have been fabricated by 17th level wizards, are alive, have a name, and are (almost) indestructible. They retain knowledge of every spell cast through them, and if their master is slain and the staff comes into possession of a lesser mage, the staff may sometimes take command of the magic-user, in effect using him as a bettery [sic] to provide power for the casting of spells. At the G.M.s option such spell casting may not always be appropriate or desired.(In later editions, the cost of a deluxe staff is 5,000 gold pieces. Such are the effects of inflation.)