The Idiot's Guide to Tarot is a good survey book on the Tarot. It covers all the information a beginner might need, but also goes into enough depth for some one at an intermediate level.
The book deals with the history and beliefs behind the Tarot, though I believe the authors have accepted stories on the Tarot's origin that do not stand up to scrutiny. Still, it is the same history as in many other books, so this is not a big problem.
The authors also cover how to choose the right Tarot deck for you, the meanings of all the cards, the significance of the major and minor cards, many different spreads and which is best for what kind of question, etc. They also spend a good deal of time on how to "read" the cards without resorting to the book meanings.
I was not completely happy with this book. The authors spend a lot of time on the relation of astrology and numerology to the Tarot, which I am not interested in, but it may interest others.
However, my main problem was that the meanings seemed off to me, especially for reversed cards. Their card meanings are different enough from what I have been taught and have seen in other books that it bothered me.
Despite those problems, the book will give you a good start or update on the Tarot and how to read it.