The reason why there is really no authority (although that's not to say there are wise ones out there with plenty of experience with the Tarot), is due to the fact that the Tarot does not follow a lineage. In fact, the exact origins of the cards are unknown. Some say that the roots can be traced back to the East, particularly the Buddhist Tantra system, who used an ancient board game that is very reminiscent of the Tarot, which was then brought westward by the Gypsy people in the 10th century. Others claim that the cards originated from secret brotherhoods of Egypt, designed for initiates. Others say they were created in Europe.
The Tarot was first recorded in history at the end of the Dark Ages, possibly introduced from the East by returning Crusaders. But during this time when the church suppressed anything that threatened to usurp the "one faith," the Tarot suffered heavy attack. The church called them the Devil's cards and towns began to burn the decks; and eventually as the Inquisition began to gain momentum, burned the readers of the Tarot as well. Due to this suppression, the Tarot soon feigned as a deck of meaningless playing cards to avoid persecution, and eventually the deeper meanings became lost or went underground. And no complete deck of those times remains. Only a smattering of cards, from various decks and periods can be found in museums or in private collections.
Books You Might Enjoy:
Aleister Crowley - The Zodiac And The Tarot
Aleister Crowley - Thoth Tarot Deck
Aristotle - On The Soul
Aleister Crowley - The World Of Tarot