The practice of tarot is many centuries old. It was played in french parlors and all across Europe as a card game, and it became a tool of prophecy in the 1600's. Although the most widely used set is the"Rider-Waite" deck, the interpretations of the deck are as widely varied as the amount of decks available.
The possibility that three random cards will tell your past, present, and future is intimidating at the least but probably not true. And still, some people refuse to ever have their cards read. It freaks them out (respectively) but there is no science behind it.