The 22 Major Arcana represent both archtypes and/or the spiritual journey that many if not most individuals take through their lives.  They can symbolize major issues, emergencies, or personality types involved in a situation, depending on their context within a spread.  They can sometimes even serve as a warning to the reader that there are lives and fortunes at stake when every card in a spread comes up in a mixed deck reading.

A spread can be done using only major arcana cards, if one knows in advance that they are reading a situation in which the personalities of the individuals involved, rather than nature or circumstance, are most relevant to the issue at hand.  They can also be used for ceremonial or meditation purposes, to indicate which deities or archtypes should be focussed on in a particular ritual or event.

Aside of the 22 standard major arcana, a deck may have a talisman.  This is the card or object intended to infuse the deck with a spiritual energy. Where it comes up in a spread, it means that there is some spiritual/magical/deep psychological significance.

The major arcana may be numbered differently depending on the deck, so we will go with the titles rather than their numerical value.  The numerical value often has to do with the culture and spirituality of the developer of the deck.

Here is a handy chart with the basic information on the 22 cards of the major arcana:
 

Card Title(s):	Associations:	General Meaning:	Reverse (or inverted) Meaning:
The Fool (Seeker, Novice, Newborn)	Fire	foolishness, brashness, naivete, enthusiasm or overenthusiasm, being in a "bhakti" state	apathy, bad decisionmaking, coldness, numbness, neglect
The Magician (Wizard, Sorcerer, Mage, Magus, Hungen, Shaman, Priest)	Air	intelligence, confidence, creativity, inventiveness, creation, ascetic male	insecurity, mental or emotional weakness, cowardice, insecurity
The High Priestess (Witch, Sorceress, Shamaness, Maga, Mambo)	Moon	ability to see what is hidden, intuition, insight, wisdom, love without sexual burdens, psychic abilities, ascetic female	superficial, lack of foresight, shallow
The Empress (Queen, Mother, Matriarch)	Durga, Yemalla, Isis, Sarasvati, planetary association with Mars	pregnancy, marriage, fertility, loyalty, gentle leadership, production, a good harvest, femininity	frigidity, bad leadership, anxiety, weakness, indecision, infertility, disloyalty, inconsistency
The Emperor (King, Father, Patriarch)	The Sun, Osiris	accomplishment, wealth, good providership, good leadership, stability, success	bad leadership, weakness, indecision, lack of self control
The Hierophant (Judge, Monk, Librarian)	Aries	kindness, generosity, great hidden potential, conservativism, stubbornness, priesthood, old fashioned	being a doormat, too much generosity and kindness, lack of self confidence, frailty, or rebellion, unorthodox views and unconventionality
The Lovers	Taurus	choices, dilemas, duality, love, romantic illusion, intense emotion, inner conflict	frustrated romance, unrequited love, failure of a test especially one of qualification
The Chariot	Gemini	travel, journey, a quest, challenges to overcome, challenges previously overcome, escape	defeat, failure, stagnation, boredom
Justice	Cancer	justice, fairness, balance, equality, righteousness, a judgement going in one's favor	injustice, unfairness, disharmony, abuse, abuse of power
The Hermit	Leo	pilgimage, solitude, being careful, time out, rejection of some aspect of worldliness	rash decisions, jumping the gun, lack of wisdom
Wheel of Fortune	Virgo	fate, destiny, karma, luck	bad luck, unanticipated problems, a monkeywrench in one's plans
Strength	Venus	courage, strength, force, intensity	cowardice, weakness, pettiness
The Hanged Man	Libra	self sacrifice, suffering for another or a cause, passivity or dullness, numbness as a result of trauma	ungenerous, unfair sacrifice, lack of willingness to sacrifice, egoism
Death	Water	death, illness, transition, a life changing shock or realization, loss, abandonment	near death experience, lack of change, lack of progress, or very slow change
Temperance	Scorpio	temperance, patience, moderation, a positive influence or sign, balance and harmony within	chaos, confusion, turmoil, failed negotiation, arguments, conflict
The Devil	Sagittarius	addiction, violence, obsession, bondage, bad influences, negative direction of energy	recovery, release, freedom
The Tower	Capricorn	catastrophe, loss of faith, sudden painful change, shock, severe trauma	traps, stagnation, routine
The Star	Mercury	hope, consolation, faith, a good sign, encouragement, inspiration	hopelessness, broken dreams, dissatisfaction
The Moon	Aquarius	deceit, lies, something hidden, espionage or hidden motives, falseness, pretentiousness	"little white lie", or a deception with good intentions (such as a surprise party), taking advantage, opportunism
The Sun	Pisces	success, achievement, complete victory, all around positive, pure	not so complete victory, compromise, things missing from one's life
Judgement	Saturn	judgement, karma, time to pay for one's crimes or reap the benefits of one's good deeds, repentance, the need to repent or make amends	clouded judgement, delusion, callousness, alienation
The Universe	Jupiter	success, fulfillment, reaching one's goals, a positive outcome	failure, disappointment