Hotkey spells: bring up list of spells by pressing 'S'. Position cursor over spell and hit F5, F6, F7 or F8 to assign that key to that particular spell. You will then be able to call up that spell by simply pressing that hot key and toggle between each easily.  Anything that can be found in book form can also be found on scrolls or staves.

A page with some info on spells that were in the beta and demo version of Diablo, but that didn't make it to the final version, can be seen here.

Icon	Name	Book/ Scroll	Description
	Apocalypse	S Staff	Hits any monsters on the screen, over walls or not.  It is the only physical damage spell, meaning it will affect fully-immune monsters.  Diablo casts it, but like any physical attack, it can be blocked.
	Bloodstar	B	Casts a ball of energy, similar to the witches in hell, reduces the enemies' hit points by 1/3 the casters magic level. Uses health as well as Mana to cast.  Magic-based spell.
	Bone Spirit	B	Casts a phantom at the enemy taking 1/3 of their hit points. Uses health as well as Mana to cast.   Magic-based spell.
	Chain Lightning	B	Sometimes referred to as spready-out lightning. Casts a web of lightning in all directions from the caster. Damages friend and foe so use cautiously when playing multi-player games.
	Charged Bolt	B	Discharges streams of electricity which travel somewhat randomly around until they hit a wall or strike a friend or enemy.  Can cause problems with the sprite limits.
	Elemental	B	A fiery phantom charges at the target exploding into a fireball on impact.  Listed damage is identical to Fireball, but it doesn't do the same splash damage, so is far less-damaging.
	Fireball	B	A rapid-fire spell packing a powerful punch. One of the most useful.  Actual damage is about twice what is listed, due to a bug in the splash damage.
	Firebolt	B	A weaker version of Fireball, but lower on the mana and much easier to read the books.   Sufficient on early levels.
	Firewall	B	A wall of fire erupts from the ground damaging anything stupid enough to stand in it, including other players. Damage and duration increase with spell level.
	Flamewave	B	Basically a moving firewall, slightly less powerful. Sweeps across a room damaging anything it comes into contact with - that is not resistant to fire of course.  Does less damage than is listed.
	Flash	B	Fast to cast and effective within an eight square radius.  Very high listed damage is inaccurate. Magic-based spell, only really effective use past normal is on nightmare Azure Drakes.
	Golem	B	This lonely old guy rises from the ground to pound his fists on any unfortunate beast that stands in his way. His Hit Points are relative to the level of the spell & the caster's total mana.  The listed damge means nothing.
	Guardian	B	Another top spell. Cast this three headed beastie and he'll spew firebolts at any enemy within range. Duration is determined by your Guardian spell level, damage is equivalent to your Firebolt spell.
	Healing	B	Heals your own wounds.  Cost to cast is proportion to your hit points and spell level.
	Heal Other	B	Heals your team mates wounds. Multiplayer only.
	Holy Bolt	B	Fires a ball of holy magic. Works only on the undead including the Big Man himself.  Good for getting Diablo out of his box without waking the others.
	Identify	S Staff	Reveals the special features of an unidentified object.
	Inferno	B	Works best when dealing with a group of enemies as it casts a jet of fire. Not terribly useful.
	Infravision	S	Allows the caster to see what monsters lurk behind walls and closed doors.  Nice to help aim your teleports over walls and also Stone Curses.
	Lightning	B	Easier to control than chain lightning. You can specify which enemy this concentrated bolt of electricity is to travel to. Not as powerful as chain.
	Mana Shield	B	Cast this spell on yourself and any damage received will be taken from your mana first rather than your health. This spell was much more effective at lvl 1, until the v1.07 patch.  Now about 20% damage absorbed at any level.
	Nova	S Staff	A blast of lightning radiates from the caster. An extremely powerful spell.
	Phasing	B	Randomly transports the caster to any spot in sight.  Works slightly faster than Teleport.   Used to get you out of sticky situations but note it could transport you into an even bigger horde of monsters.
	Resurrect	S StaffS	Breathes life back into a fallen companion. Multiplayer only.
	Stone Curse	B	Turns your target to stone. The time they remain in this state is determined by the level of the spell, though it maxes out at lvl nine.
	Telekinesis	B	Allows manipulation of objects from a distance. Opening doors, chests, pushing monsters back and picking objects up. Handy in hell for moving levers, or for recovering your items after death.
	Teleport	B	Excellent panic-button this one. Teleports user to a specified location within view.  Extremely useful spell for time-saving, as well as quick escapes.
	Town Portal	B	Casts a gateway to town from any level of the dungeons. Will last until the caster returns to the dungeons through it. Each player can have only one portal open at any time.