IT'S AN ORACLE FOR ANSWERING QUESTIONS.......
The biggest misconception about the tarot is in not understanding that it's predominantly meant to be used as an oracle for answering questions. This is why a lot of readers will ask you what you want answers to; it's not because they're trying to pump you for information - it's because this is how the tarot works best.
The origins of the tarot are unclear. There are claims of its having begun in Ancient Egypt, whilst others suggest that it started within the mystery cults of the Mithras during the first few centuries A.D. Others believe it originated in Celtic times, at the time of the mythology surrounding the Holy Grail or during the Middle Ages. Whatever its origins, it's a form of divination (much like Astrology, Runes or Palmistry) and is not based on any religion.
There are numerous types of tarot "deck" these days - in fact there are so many that it may be hard to choose one, if you're interested in learning to read them yourself! The pictures can come from different mythologies, or these days some are based on popular culture. They're often very aesthetically pleasing - but the pictures are partly a tool for the reader to focus, much as a healer or medium may use.
The real skill is in synthesizing the meanings based on the positions of the cards in an individual "spread" (how the cards are laid out), as different positions in a spread or a different context can affect the way in which they're interpreted.
The tarot's symbolism is "universal", which means that its symbols are recognised by the unconscious as having the same meanings within every belief system's symbology, whether secular or religious (and this is amazing in itself!) suggesting something "other" that we all recognise on a deep level. Indeed, both Carl Jung, the famous psychoanalyst and Goethe, the dramatist, philosopher and theologian, studied this view and believed that symbols e.g. a triangle, meant something specific to us on an unconscious level.