Three word summary - Expensive Batshit lunacy.

It's supposedly a religion-type organization that can help you be the best person you can be, and maximize your potential. If you pay them a lot of money, they will teach you how. Detractors say the methods they teach are just a fraud. One description I read was a machine that would strengthen your brain waves, only it was really just a couple of orange juice cans with some wires sticking out of it which didn't even have any actual connection to the "brain machine" machine that had blinking lights on it.

I think your question answered itself...

According to Scientology when you enter the organization or after you've paid a few thousand dollars? Scientology is, according to its own texts, the "the study and handling of the spirit in relationship to itself, others and all of life." Prime among Scientology's beliefs is: "that man is a spiritual being whose existence spans more than one life and who is endowed with abilities well beyond those which he normally considers he possesses." The purpose of Scientology is "to know"; to achieve complete certainty of one’s spiritual existence and one’s relationship to the Supreme Being. Scientology says its practice provides exact and precise methods by which a person can achieve greater spiritual awareness. After paying a few thousand dollars, Scientology then teaches this really bad sci-fi story about aliens killing other aliens by stacking them around volcanoes and nuking the volcanoes. The alien souls supposedly stick to everyone's body and cause disease and mental illness. I recommend a more thorough reading of the sources I used for this answer, as they're much more straightforward than what you'll find on the Church of Scientology's website. Sources: http://en.wikipedia.org/wiki/Scientology_beliefs_and_practices http://www.xenu.net/archive/leaflet/xenuleaf.htm http://www.xenu.net/archive/infopack/

To quote Stableboy in his summation of Scientology, "Life is a wallet and you have to dig deep to know the truth."