Originally tarot were used for divinatory purposes. Tarot now a days are used as tool for reflection on one's personal life, as well as an aid to meditation.
Today's Tarots have become far more interesting, expressive, and psychologically resonant than their ancestors were. Interpretations have co-evolved with the cards over the centuries: later decks have clarified the pictures in accordance with their perceived meanings, the meanings in turn modified by the new pictures. Both images and interpretations have been continually reshaped, partly at random and partly in conscious or unconscious efforts, so that Tarot live up as powerful occult instrument.
The most popular deck today is probably the fully-illustrated deck commonly known as the Rider-Waite-Smith, Waite-Smith, Rider-Waite, or simply the Rider deck. The images were painted by artist Pamela Colman Smith, to the instructions of academic and mystic Arthur Waite, and published by the Rider Company. Mass popularity began in 1910, with the publication of the Rider-Waite-Smith Tarot, which took the step of including symbolic images in the minor as well the major arcana. In the twentieth century, a huge number of different decks were created.
The Tarot is a 78-card deck structured into two distinct sets. The first, called the Major Arcana, consists of 22 cards typically referred to as trumps. Arcana mean hidden truth or secret knowledge. The second, called the Minor Arcana, consists of 56 cards divided into four suits namely cups, wands, pentacles, and swords.
The twenty-two cards in the major Arcana are: Fool, Magician, High Priestess, Empress, Emperor, Hierophant, Lovers, Chariot, Strength, Hermit, Wheel of Fortune, Justice, Hanged Man, Death, Temperance, Devil, Tower, Star, Moon, Sun, Judgment and World.
The four suits in the minor Arcana are associated with the four elements: Swords with air, Wands with fire, Cups with water and Pentacles with earth; each consist of series ace, king, queen, chariot, page, two, three, four, five, six, seven, eight, nine and ten.
The interpretations all varies with upright and reverse cards.
Divination, or fortune-telling, is by far the most popular and well-known use of the Tarot. This is sometimes seen as an extension of the psychological use. Tarot can give you insights into the future without having any supernatural or occult aspect at all but Divination may be seen as magical in itself. Meaning may emerge even from purely random patterns, or can emerge from almost any selection of cards.