By some definitions, Tarot cards are a gateway. This function has several different interpretations. To some, they are a gateway between the conscious and the un-conscious self. To others, they are a gateway between the reader and spirit guides. Still others believe they are a gateway between the reader and stronger invisible forces. Fundamentalist Christians are generally the only people who truly believe these invisible forces are Satanic or even demonic. Many, however, do believe that semi-divine entities, the good, the bad and the in-between, can communicate through cards.
Voodoo is not the only religion that embraces this concept. Divination has long been thought of as a bridge between the human and the divine, (note the very similarity in names), with cards or other physical objects acting as a bridge or gate between the two. All sorts of icons serve similar functions, (though not in the divining sense, in the bridging the gap between human and divine sense), in many contemporary religions. In fact, the early Catholic Church used tarot cards as a teaching tool at one point.
Divination has always been a part of the Vodun and Voodoo religions. In America, Tarot has become one of the primary, if not the primary method for practitioners. "The New Orleans Voodoo Tarot" was designed by, and to some extent for, these. The images on the cards and the meanings behind them, represent the Loa or sacred spirits of Voodoo. By reading them, you see which of these are active in your life, among other, more usual divinitory insights.
You don't have to practice Voodoo to use the Tarot. You will find yourself, however, feeling like you must be by the time you're done with your first reading. The deck so comprehensively illustrates the principals of the tradition it celebrates that one wonders if by reading about the Loa, one isn't actually inviting them in. If the cards are, in fact, as Voodooists believe, a way to communicate with these spirits, I suppose you are.
Each card not only represents a Loa or an aspect of one, but has on it a veve, or design whose purpose is to draw the Loa specific to it in. In Voodoo rituals, these intricate, often strikingly beautiful designs are drawn on the floor with cornmeal. Most feature a crossroads, the sacred place where Voodooists believe this world and the spirit world intersect.
So proceed with caution. Voodoo is, after all, the oldest living religion in the world. There are reasons things survive for that long and those reasons generally have something to do with the surviving thing producing rather striking results. You may well find that this deck gives the most accurate readings you've ever had, (it does), but I suggest at least buying another book about Voodoo to go with it, (I suggest the "Haitian Voodoo Handbook" by Kenaz Filan).
I don't warn because Voodoo is bad, it's a religion and as al religions do, it addresses both good and bad. However, bad things can happen when you approach powerful things naievely. The cards, in this instance, might just be truly powerful things. Read the book that accompanies them all the way through before reading, at least, so that you have some understanding of them.
This is the only Tarot book I've ever read, and I've read a lot of them, that truly engaged and engrossed me. Reading it is a wonderful way to learn about Voodoo and the many colorful Gods and Goddesses,(though they're not quite that, more like Saints), that are revered in the tradition. The artwork is remarkable and often striking, communicating complex and ancient concepts with bold, simple designs with images from modern day New Orleans.