Gnosticism was perhaps the most dangerous heresy that threatened the early church during the first three centuries. Influenced by such philosophers as Plato, Gnosticism is based on two false premises. First, it espouses a dualism regarding spirit and matter. Gnostics assert that matter is inherently evil and spirit is good. As a result of this presupposition, Gnostics believe anything done in the body, even the grossest sin, has no meaning because real life exists in the spirit realm only.
The Gnostic Empire Strikes Back: An Old Heresy for the New Age
By: Peter Jones
http://www.christianbook.com/gnostic-empire-strikes-back-heresy-age/peter-jones/9780875522852/pd/5522858?event=AFF&p=1011693&
Its a philosophy who's allegory's were never understood by the early christian church and were thus persecuted as heretics and all but exterminated. Its still not generally understood by the western world because of those same allegory's, unless one understands the significance of their symbol's it is very hard to understand, this is perhaps what led to a belief that Gnosticism was a secret knowledge.
The creators of the world Yaldabaoth Saklas Samael, the rebel,the fool and the ignorant are only aspects of mankind and not some ethereal being or angel.
On a whole Gnosticism is an interesting philosophy/religion that incorporates both Judaic and far eastern concepts of existence, it is based on knowledge as being the key to life, and that Ignorance is the cause of evil in this world, not too dissimilar to Buddhism and Taoism.
It all depends witch Gnosticism you are asking about,I am a Cristian Gnostic,but my beliefs are derived from another gnosticism more ancient,that goes back on time all the way to the god Thoth.are you familiar with that? any way,if you are asking about this Gnosticism...well,it,s very cool,nothing to do with religion,in a way we are mystics to.I recommend you research about it and try it.