Are there secret documents in scientology?

Are there secret documents in Scientology, or have people made it up to make people not trust Scientology and that they are hiding things?

Proof is appreciated over 1 liners.

http://xenu.net/

http://en.wikipedia.org/wiki/Scientology

Scientology is a cult. It is for morons like Tom Cruise and other Hollywood Stars.

who cares it's all BS anyway

It's a bogus cult started by a cartoon writer. He took some teachings from the Vedas and twisted them to fit his idea. Spiritual knowledge is free. You may have to pay for books, but that rascal charged a fortune for his seminars. Our relatives after years and thousands of dollars got disgusted with the whole thing. It's just one idea on the mental platform religion.

Yes you go through levels in Scientology and in the final level your handed a gilt edged scrolled parchment that when you open says "YOU'VE BEEN CONNED SUCKER!!"

If they were secret how would anyone know of their existence?

There are various documents in Scientology which are secret. Scientology is a very secretive organization on a variety of levels including their financial, legal and organizational dealings. However I think the secret documents the questioner is referring to are the ones which contain OT3 level information.
After many years and much money spent in Scientology training, (often a persons entire life savings is sucked up by the organization), a person is able to gain access to "higher level" information, special secret revelations that only people who are "in deep" get to learn about. The nature of this material is too complicated to go into here but suffice to say it is an outright hoax, Luckily, the exact nature of this "information" is revealed here:
WNW.xenu.net/archive/leaflet/#comments
Near the top of this page you will see a section that says "download your preferred language." In this down loadable leaflet is a detailed description on the "secret information" described above.

Absolutely. There are many secret documents.

See this link: http://www.cs.cmu.edu/~dst/OTIII/
and this one: http://www.xenu.net/archive/ot/
and this one: http://www.neverending.org/scientology/

There are no secrets in Scientology. You can go into a Scientology church or mission any time. Scientology books, recorded lectures and other materials are available to anyone.

The route or "bridge" to spiritual freedom is laid out exactly in a sequence of steps or levels. This charted route is also fully available to anyone. However the content and specific procedures of some of the upper or higher levels are confidential. The reason for this is simply that the states of the lower levels must be fully attained in sequence before doing the next. This is the pr oven successful way to do it. There is no mystery involved it is simply what works best for individuals wishing to cross this bridge. Trying to do things out of a proper sequence simply doesn't work.
Have you ever tried to clime a ladder by putting your foot in one of the upper rungs before you have stably gained the lower ones??