Michael Dummett's Game of Tarot (London: Gerald Duckworth & Co., Ltd., 1980) is out of print, and is very difficult to find, but is the ultimate source on the history of the tarot. It is impeccably researched and extremely scholarly, and puts in their final and well-deserved resting place all the various crack-pot 19th-century theories of the origins of the tarot, including the theory that it came from the ancient Egyptians and was the "Book of Thoth," etc. If you can find a copy at the local university library, it is worth taking a look at. Suffice it to say that the tarot as we know it is very much a product of late medieval and early Renaissance Christian Europe, specifically of northern Italy. Understanding and accepting this is key to understanding the symbols of the tarot, where they came from, and what they might have meant to their creators.
Stuart R. Kaplan's three volume Encyclopedia of Tarot (U.S. Game Systems: 1977 - 1990) is also an excellent resource. It still appears to be in print, and can be purchased at a very affordable price. It has tons of information on every aspect of tarot, including the history and rules of the game, the occult lore and interpretation that developed in the eighteenth and nineteenth centuries, and tarot numismatics. It also contains information on hundreds of different decks, with lots of black and white and full color images of cards.
The most useful book on tarot interpretation I've ever found is another little out-of-print book by John Shepherd called The Tarot Trumps: Cosmos in Miniature (Wellingborough, Northamptonshire: The Aquarian Press, 1985). This lovely essay on the tarot discusses the imagery of the tarot trumps in historical and cultural context, considering the influence of late medieval Christianity, astrology, Greek and Roman mythology (which was experiencing a revival in the early Renaissance period that produced the tarot), as well as literary and popular culture in northern Italy. Whether or not you buy his astrological associations -- though he makes a persuasive case for them -- this is by far the most interesting and useful exploration of the meaning of the symbolism in the cards. Another interesting essay on the tarot trumps that takes renaissance European culture into account is a brief essay by Joseph Campbell entitled "Symbolism of the Marseilles Deck," printed in Tarot Revelations (San Anselmo, CA: Vernal Equinox Press, 1987), by Richard Roberts.
I appreciate Rachel Pollack's basic approach to tarot reading. Her two-volume Seventy-Eight Degrees of Wisdom is still a classic (London: The Aquarian Press, 1980). Her Tarot Readings and Meditations (London, Aquarian Press, 1990) I have also found helpful. Evelin Burger and Johannes Fiebig, Complete Book of Tarot Spreads (New York: Sterling Publishing Co., Inc., 1997) can help break you out of the Celtic cross blues with lots of ideas for different kinds of tarot spreads. Finally, despite the hokum, I really like Oswald Wirth's The Tarot of the Magicians (York Beach, ME: Samuel Weiser, Inc., 1985, originally published in Paris, 1927, under the title Le Tarot, des Imagiers du Moyen Age). This book contains all kinds of creative approaches to tarot symbolism, from numerology to cabalism to astrology to color interpretation. S.L. MacGregor Mathers' The Tarot: A Short Treatise on Reading Cards (York Beach, ME: Samuel Weiser, Inc., 1969, originally published as a pamphlet in 1888) is a good source on "traditional" interpretations of all the cards for fortune-telling.
I find that the best approach to tarot interpretation is to let go of any hard and fast rules. I have read a lot about tarot (accumulated quite a library), including the late nineteenth and early twentieth-century occult works, as well as more recent books on tarot interpretation. When I interpret the cards, I try to relax and allow associations to emerge free-form based on my knowledge of the history of the cards and the symbolism in them. I take into account the positions of the cards in relation to one another, whether they are upright or inverted, look at colors, look at numbers, see if any stories seem to emerge.
Nevertheless, I have found it very helpful to memorize a few basic interpretive keys. What follows are the interpretive keys that I have found most helpful.
 | The Fool A fool. Everyman. Foolishness disguised as wisdom. Wisdom disguised as foolishness. Paradox. Possibility. The unpredictable. Divine providence. God. Numerological association: 0; non-existence; the creation ex nihilo; the ouroboros |
 | The Magician "The little man." A conjurer, an illusionist, a manipulator. A showman. Change and transformation. Dreams. Numerological association: 1; the self; the will Astrological association: Moon in Cancer |
 | The Papess Pope Joan. Mother Church. The body of Christ. The link between the Pope and the people. Knowledge. Teacher. Divine messenger. Keeper of mysteries and divine secrets. Numerological association: 2; duality; sexual ambiguity; hermaphroditism; good and evil Astrological association: Mercury in Gemini |
 | The Empress Influence through attraction. Desire. Pleasure. Love. Beauty and harmony. Good things. Materialism. Emotion. Numerological association: 3; fertility; creativity; trinity; soul Astrological association: Venus in Taurus |
 | The Emperor The Holy Roman Emperor. World ruler. Military strength and temporal power. Action, force and energy. Numerological association: 4; physicality; stability; the four directions; the four winds; the material world Astrological association: Mars in Aries |
 | The Pope The Holy Father, the Vicar of God, the Head of the Church. Spiritual power. Power and authority in Heaven and Earth. Sympathy and compassion. Faith (one of the three theological virtues). Numerological association: 5; humanity; mortality Astrological association: Jupiter in Pisces |
 | The Lover Love, the beginning and end of mortal existence. Generative Power. The trial by fire. Numerological association: 6; spiritual union; spiritual harmony; atonement Astrological association: "Iliaco"; Angel of the Sun; heliacal rising |
 | The Chariot Triumph. The spirit of life. Vitality. The soul driving the body. Mastery of the spiritual and sensual. Numerological association: 7; triumph, union of body (4) and soul (3) Astrological association: Sun in Leo |
 | Justice The goddess Astraea. Justice (one of the four cardinal virtues). Law and its correct application. Right conduct. Discernment. The search for truth. Numerological association: 8; justice; balance; division Astrological association: Mercury in Virgo |
 | The Hermit "The old man." Contemplative religion, inner faith. Withdrawal from the material world. Prudence (one of the four cardinal virtues). Time. Numerological association: 9; the end of a cycle; the angelic orders; the grand climacteric (old age) Astrological association: Saturn in Aquarius |
 | The Wheel of Fortune The goddess Fortuna. The temptation of greed, avarice, and ambition. The triumph of charity (one of the three theological virtues) over greed. Desire ruled by love. Numerological association: 10; the beginning of a new cycle Astrological association: Venus in Libra |
 | Strength Fortitude (one of the four cardinal virtues). Spiritual and moral courage. Physical steadfastness and perseverence. Numerological association: 11; imperfection; the struggle against vice Astrological association: Mars in Scorpio |
 | The Hanged Man "The traitor." Change of allegiance. Reversal of point of view. Preparation for death. Suspension between Heaven and Earth. Spiritual mindedness. Turn toward a higher point of view, toward expanded consciousness. Self-sacrifice. (A Christ figure.) Numerological association: 12; grace and perfection; the closed circle; the zodiac Astrological association: Jupiter in Sagittarius |
 | Death Gateway into immortality. Passage into the spiritual realm. Transformation. Numerological association: 13; the last supper; death Astrological association: Saturn in Capricorn |
 | Temperance Ceres. Temperance (one of the four cardinal virtues). Self-restraint, sobriety, moderation, chastity. Tempering, regeneration, renewal, dissolution and solution. Psychopomp. Numerological association: 14; helpers and protectors; lunar transformation (14 days from the waxing to the waning moon and vice versa); the ending of one era and the beginning of a new Astrological association: "Chronico"; Angel of the Moon |
 | The Devil Satan. Hades. Energy, ambition, and pride. Disruption and trouble. Numerological association: 15; lunar zenith; magic Astrological association: Mars in Capricorn Angelic association: Samael |
 | The Tower "The House of the Devil." The Tower of Babel. Divine justice. The punishment for sin. A hellmouth. Gateway between worlds. Numerological association: 16; wholeness; perfection; four squared Astrological association: Mercury in Virgo Angelic association: Raphael |
 | The Star Proserpine. Rebirth. Spring. Fertility. Hope (one of the three theological virtues). Numerological association: 17; conquest; warfare and heroism Astrological association: Venus in Pisces Angelic association: Anael |
 | The Moon The shorter cycles; temporality. The midpoint between Earth and Heaven; between Hell and Heaven. The frontier between Time and Eternity. Crossroads. Choices. Numerological association: 18; faith through good works; fulfillment of the law Astrological association: Moon in Taurus Angelic association: Gabriel |
 | The Sun Apollo. Life force. Divine love. Light and truth. The entry into Heaven. Numerological association: 19; completion of the heavens (12 signs of the zodiac plus 7 planets) Astrological association: Sun in Aries; "Cosmico," Lord of Generation Angelic association: Michael |
 | Judgment "Christ the King." Entrance into eternity. Resurrection, immortality. Awakening or rebirth into higher consciousness. Numerological association: 20; sun; zenith; the highest point Astrological association: Jupiter in Cancer Angelic association: Sachiel |
 | The World God the Father. Anima mundi. The fifth element. The squaring of the circle. The whole. The New Jerusalem. Heaven. The new world beyond time. The supreme end. Numerological association: 21; divine perfection (7 times 3) Astrological association: Saturn in Libra Angelic association: Cassiel |
 | King of Wands Education. Honesty. A country gentleman. A dark man. Possible inverted association: Counsel. Naturally good but severe man. Suit association: intuition, thinking; fire, the people Rank association: extroversion, judging |
 | Queen of Wands Business minded. A country woman. A dark woman. Possible inverted association: Obstacles. A good and virtuous woman, but strict. Suit association: intuition, thinking; fire, the people Rank association: extroversion, perceiving |
 | Knight of Wands Departure. A dark young man. Possible inverted association: Rupture. Quarrel. Suit association: intuition, thinking; fire, the people Rank association: introversion, judging |
 | Valet of Wands Pleasure. Good stranger. Postman. Lover. A dark youth. Possible inverted association: Chagrin. Ill news. Suit association: intuition, thinking; fire, the people Rank association: introversion, perceiving |
 | Ten of Wands Oppression. Good faith. Possible inverted association: Subterfuge. Duplicity. Suit association: intuition, thinking; fire, the people Numerological Association: change, renewal |
 | Nine of Wands Strength. Order. Possible inverted association: Displeasure. Obstacles. Suit association: intuition, thinking; fire, the people Numerological Association: completion, mystery |
 | Eight of Wands Swiftness. Desire. Possible inverted association: Quarrels. Intestine disputes. Suit association: intuition, thinking; fire, the people Numerological Association: law, conflict |
 | Seven of Wands Valor. Victory. Possible inverted association: Doubt. Embarassment. Suit association: intuition, thinking; fire, the people Numerological Association: inspiration, greater fortune |
 | Six of Wands Hope. Wish. Possible inverted association: Disloyalty. Treachery. Suit association: intuition, thinking; fire, the people Numerological Association: interrelatedness, creation |
 | Five of Wands Strife. Gain. Possible inverted association: Judgment. Law. Lawyer. Suit association: intuition, thinking; fire, the people Numerological Association: mortality, humanity |
 | Four of Wands Concord. Association. Possible inverted association: Prosperity. Advantage. Suit association: intuition, thinking; fire, the people Numerological Association: materiality, the world |
 | Trey of Wands Undertaking. Enterprise. Possible inverted association: Hope. Wish. Suit association: intuition, thinking; fire, the people Numerological Association: fecundity, lesser fortune |
 | Deuce of Wands Sadness. Wealth. Possible inverted association: Surprise. Extraordinary occurrence. Suit association: intuition, thinking; fire, the people Numerological Association: duality, balance |
 | Ace of Wands Creation. Birth. Possible inverted association: Persecution. Tyranny. Suit association: intuition, thinking; fire, the people Numerological Association: unity, purity |
 | King of Cups Generosity. Creativity. Man of divinity. Businessman. Lawyer. Possible inverted association: Suspicion. Man of good position, but shifty. Suit association: intuition, emotion; water, the clergy Rank association: extroversion, judging |
 | Queen of Cups Pleasure. Gift of vision. Good mother. A fair woman. Possible inverted association: Success. Trouble. A woman of good position, but intermeddling and untrustworthy. Suit association: intuition, emotion; water, the clergy Rank association: extroversion, perceiving |
 | Knight of Cups Arrival. Dreamer. Possible inverted association: Cunning. Duplicity. Suit association: intuition, emotion; water, the clergy Rank association: introversion, judging |
 | Valet of Cups Worthy of confidence. Studious youth. A fair youth. Possible inverted association: Deception. A flatterer. Suit association: intuition, emotion; water, the clergy Rank association: introversion, perceiving |
 | Ten of Cups Perfect love. Home town. Possible inverted association: Differences. Violence. Suit association: intuition, emotion; water, the clergy Numerological Association: change, renewal |
 | Nine of Cups Trials overcome. Victory. Possible inverted association: Liberty. Imperfections. Suit association: intuition, emotion; water, the clergy Numerological Association: completion, mystery |
 | Eight of Cups Renunciation. A fair girl. Possible inverted association: Pleasure. Feasting. Suit association: intuition, emotion; water, the clergy Numerological Association: law, conflict |
 | Seven of Cups Imagination. Projects. Possible inverted association: Will. Plan. Suit association: intuition, emotion; water, the clergy Numerological Association: inspiration, greater fortune |
 | Six of Cups The past. New knowledge. Possible inverted association: The future. Renewal. Suit association: intuition, emotion; water, the clergy Numerological Association: interrelatedness, creation |
 | Five of Cups Loss. Marriage. Inheritance. Possible inverted association: Return. News. False projects. Suit association: intuition, emotion; water, the clergy Numerological Association: mortality, humanity |
 | Four of Cups Ennui. Blended pleasure. Possible inverted association: Presentiment. New acquaintance. Suit association: intuition, emotion; water, the clergy Numerological Association: materiality, the world |
 | Trey of Cups Plenty. Victory. Possible inverted association: Excess. Expedition. Suit association: intuition, emotion; water, the clergy Numerological Association: fecundity, lesser fortune |
 | Deuce of Cups Love. Friendship. Possible inverted association: Crossed desires. Obstacles. Suit association: intuition, emotion; water, the clergy Numerological Association: duality, balance |
 | Ace of Cups Contentment. Communion. Possible inverted association: Inconstancy. Metamorphosis. Suit association: intuition, emotion; water, the clergy Numerological Association: unity, purity |
 | King of Swords Authority. Judgment. Lawyer. Possible inverted association: Chagrin. A wicked man. Suit association: sensing, thinking; air, the nobility Rank association: extroversion, judging |
 | Queen of Swords Privation. Widow. Possible inverted association: Riches. Discord. Ill-tempered and bigoted woman. Suit association: sensing, thinking; air, the nobility Rank association: extroversion, perceiving |
 | Knight of Swords Skill. Soldier. Possible inverted association: Ingenuousness. A conceited fool. Suit association: sensing, thinking; air, the nobility Rank association: introversion, judging |
 | Valet of Swords Overseeing. Spy. Possible inverted association: Vigilance. Support. Suit association: sensing, thinking; air, the nobility Rank association: introversion, perceiving |
 | Ten of Swords Death. Affliction. Possible inverted association: Power & authority. Momentary advantage. Suit association: sensing, thinking; air, the nobility Numerological Association: change, renewal |
 | Nine of Swords Despair. Priest. Conscience. Possible inverted association: Wise distrust. Shady character. Suit association: sensing, thinking; air, the nobility Numerological Association: completion, mystery |
 | Eight of Swords Censure. Imprisonment. Possible inverted association: Accident. Past treachery. Suit association: sensing, thinking; air, the nobility Numerological Association: law, conflict |
 | Seven of Swords Attempt. Wish. Possible inverted association: Prudence. Wise advice. Suit association: sensing, thinking; air, the nobility Numerological Association: inspiration, greater fortune |
 | Six of Swords Voyage. Envoy. Possible inverted association: Revelation. Love proposed. Suit association: sensing, thinking; air, the nobility Numerological Association: interrelatedness, creation |
 | Five of Swords Destruction. Affliction. Possible inverted association: Same as upright meaning. Suit association: sensing, thinking; air, the nobility Numerological Association: mortality, humanity |
 | Four of Swords Retreat. Monk. Tomb. Possible inverted association: Economy. Precaution. Suit association: sensing, thinking; air, the nobility Numerological Association: materiality, the world |
 | Trey of Swords Rupture. Nun. Possible inverted association: Error. Disorder. Suit association: sensing, thinking; air, the nobility Numerological Association: fecundity, lesser fortune |
 | Deuce of Swords Truce. Friendship. Possible inverted association: Lies. False friends. Suit association: sensing, thinking; air, the nobility Numerological Association: duality, balance |
 | Ace of Swords Force. Victory. Possible inverted association: Hopeless love. Obstacles. Suit association: sensing, thinking; air, the nobility Numerological Association: unity, purity |
 | King of Coins Bravery. Mathematician. Businessman. A dark man. Possible inverted association: Fear. A vicious and dangerous man. Suit association: sensing, emotion; earth, merchants Rank association: extroversion, judging |
 | Queen of Coins Generosity. A dark woman. Possible inverted association: Obstacles. A good and virtuous woman, but strict. Suit association: sensing, emotion; earth, merchants Rank association: extroversion, perceiving |
 | Knight of Coins Economy. A useful man. Possible inverted association: Idleness. A brave man but unemployed. Suit association: sensing, emotion; earth, merchants Rank association: introversion, judging |
 | Valet of Coins Economy. Studious youth. A dark youth. Possible inverted association: Dissipation. Prodigality. Suit association: sensing, emotion; earth, merchants Rank association: introversion, perceiving |
 | Ten of Coins Family. Wealth. Possible inverted association: Dissipation. Robbery. Gambling. Suit association: sensing, emotion; earth, merchants Numerological Association: change, renewal |
 | Nine of Coins Prudence. Accomplishment. Possible inverted association: Bad faith. Deceit. Suit association: sensing, emotion; earth, merchants Numerological Association: completion, mystery |
 | Eight of Coins Work. A dark girl. Possible inverted association: Hypocrisy. Usury. Suit association: sensing, emotion; earth, merchants Numerological Association: law, conflict |
 | Seven of Coins Profit. Gain. Possible inverted association: Melancholy. Anxiety. Suit association: sensing, emotion; earth, merchants Numerological Association: inspiration, greater fortune |
 | Six of Coins Charity. Gifts. Possible inverted association: Ambition. Longing. Suit association: sensing, emotion; earth, merchants Numerological Association: interrelatedness, creation |
 | Five of Coins Ruin. Mistress. Possible inverted association: Imprudence. Disgraceful love. Suit association: sensing, emotion; earth, merchants Numerological Association: mortality, humanity |
 | Four of Coins Clinging. Enjoyment. Possible inverted association: Suspense. Obstacles. Suit association: sensing, emotion; earth, merchants Numerological Association: materiality, the world |
 | Trey of Coins Craftsmanship. Aristocracy. Possible inverted association: Mediocrity. Children. Suit association: sensing, emotion; earth, merchants Numerological Association: fecundity, lesser fortune |
 | Deuce of Coins Play. Letters. Possible inverted association: Enforced gaity. Composition. Suit association: sensing, emotion; earth, merchants Numerological Association: duality, balance |
 | Ace of Coins Contentment. Gold. Possible inverted association: Mammon. Bad intelligence. Suit association: sensing, emotion; earth, merchants Numerological Association: unity, purity |