A. History

The Tarot is a large and complex deck of cards, commonly used for divination and fortune-telling.  The origins of the Tarot are uncertain; though it is frequently considered to have begun in  Egypt, the evidence for an Egyptian origin is shaky. What is certain  is that Tarot cards and decks were known in Europe in the 14th and 15th centuries.  At that time, they were most commonly used  for playing card games, rather than for divination, and many variants of the basic deck were tailored to fit the rules of specific games.  By about the 18th century, however, the focus began to shift, and the Tarot became a divination tool.  The contents of the  Tarot became largely stabilized as a system of "reading" the cards developed. Finally, in the early 20th century, Edward Arthur Waite developed the form of Tarot (made famous by the still-popular  Rider-Waite Tarot deck) that is considered the "classic" today.

B. Structure

The Tarot is actually made up of two different card decks fused  together.  The first is called the Major Arcana, and consists of 22 cards numbered 0 through 21.  These are the "named" cards most  commonly associated with the Tarot-- such as Death, The Fool,  The Lovers, etc.  The Major Arcana stand for powerful, archetypal forces, and are considered to have particularly strong influences in a reading. 

The remaining 56 cards of the Tarot are called the Minor Arcana, which are more concerned with lesser, everyday forces and meanings.  They are divided up into 4 different suits (swords, cups, wands, and pentacles), just as a modern deck of playing cards is divided into suits.  In fact, playing cards were probably developed from the Tarot, back when the Tarot was a playing deck.  The Minor Arcana still shares many similarities with playing cards; each Minor Arcana suit is made up of an ace, cards numbered 1-10, and the 4 Court Cards--Page (or Princess), Knight, Queen, and King.  The similarity between the Minor Arcana and playing cards is so strong that their suits are equivalent (swords = spades, cups = hearts, wands = clubs, and pentacles = diamonds), and the two decks can even be substituted for one another, either for games or divination!  The only real differences, besides the artwork, are the presence of the Page in the Tarot deck (which has no playing card  equivalent, since Knights and Jacks are considered to be interchangeable), and the presence of a Joker in the playing deck  (although some people think the Joker is a variant of The Fool  from the Major Arcana).¹