Satanism is very different from the worshipping of the Christian Satan, or demons. It's an atheistic philosophy of life, celebrating man's carnal instincts, and not to supress your indulgences. Anton Szandor LaVey was the first person to give this way of living a life, and he chose Satanism. If Satanism has nothing to do with the Devil or demons, why does it have the word Satan in it? Satan is a symbol for indulgence, for what other people perceive as "evil". We believe that man is God, so birthdays are the most important of the Satanic holidays. The other Satanic holidays are the Solstices, and Walpurgisnacht (Hallow's Eve). The symbol of Satanism is the pentagram, with the head of Baphomet in it. There are nine Satanic statements, and eleven Satanic Rules of the Earth. The Satanic Bible was released in 1966, written by LaVey. It contains the books of Satan, Lucifer, Belial, and others. As well, it contains the Thirteen Keys, translated by LaVey himself. So, in short, forget what people tell you about Satanism. It's not doing drugs, killing children, or sacrificing animals, it's a celebration of indulgence and man's body.
"dude, you worship the Devil!"
"no, I practice Satanism"
"go read the Satanic Bible, you ignorant wretch of a human being"
Anton Szandor LaVey was born in 1930. He was the first person to introduce the ideas of indulgence into a religion, Satanism. It all started one night in the 1960's; LaVey shaved his head bald, and later wrote the Satanic Bible, among others. He gave many interviews and published many books before his death in 1997. He sparked a controversial way of life which has been misunderstood by most, but to Satanists, he remains an important man in religious history. And no, he never killed any children or did drugs.
"who's that weird bald guy?"
"that's Anton Szandor LaVey, the founder of Satanism"