Unfortunately there's a phenomenon of ignorance around the realm of Satanism. People who aren't Satanists often cower in fear of the word. And it's understandable why they do: Hollywood, and in cases where followers take the idea of this religion to extreme heights, give a rather inaccurate portrayal of what Satanism actually is, thus overshadowing what it's supposed to be about. And in the process giving non-followers and non-practitioners reasons to be scared.
"Dial 666" is the title of another story idea I've just come up with: This one would be a fictional tale about the followings into the realm of Satanists/Satanism, an accurate-as-possible portrayal of what Satanism is really about, and what it's really for. I don't know yet how I will come to write this story. I might have to go undercover-style to get a real look into some of the things people are doing. But I can tell you—no, promise you—it's not actually all '666! Call on the devil to feed off our souls and pray on sheep and slaughter animals' b.s. that you've seen or heard on the TV.
In all actuality it's actually a peaceful movement. There are two types: Atheistic and Theistic. "atheistic Satanist beliefs emphasize personal development and free thought...the most direct path to individual fulfillment and self-actualization" (Thorpe). (I personally put those words in bold to differentiate the terms more clearly). Meanwhile there are the theistic Satanists in which "the vast majority of theistic Satanists do not see Satan as a destructive figure of absolute evil, neither do they typically practice an inverted form of Christianity. Rather, they view the God of the Abrahamic faiths as a vengeful deity, who seeks to enslave or oppress humanity" (Thorpe).
I don't know how I'd even start to write a book on this, but there you have it.
Note: all informative quotes on Satanism comes from an article titled What Is the Difference Between Wiccans and Satanists? by Aaron Thorpe. If you wish to read more on this, follow the link in red bold