Stella: here is a good overview of the Gnostic gospels which were hidden, destroyed and denied by the church and vatican
http://www.earlychristianwritings.com/gnostics.html
This is just one of many pages on them
the reason they were hidden away and destryoed (obviously not all copies) by the church was because many of them went against the general direction of the new testament and the church, the gnostic gospels (and one apparently written by jesus christ himself) said to not believe in a god or higher being but rather to believe in oneself and just be a good person
and treat others the way you would want to be treated..etc.
You can obviously see why the church had a problem with information like that being let loose, esp. in the dark ages where the church seemed to be people's salvation and hope.
You can also see another reason why the Roman Catholic Church had a problem with it: IT'S CATEGORICALLY FALSE, according to the teachings of Jesus Christ. Jesus NEVER taught (nor did His disciples, or the apostle Paul) to simply be good.
Paul stated in Romans 10:9,
If thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved..
The words of Jesus Christ,
"I am the way, the truth, and the life. No man cometh unto the Father, but by me (John 14:6).
During His ministry, Jesus Christ told others about the Ten Commandments. And, Both the Old and New Testaments sum up the Commandments as this:
Love the Lord thy God with all that heart, soul, and strength ("Do not have any gods before me; You shall not make unto thee any graven images; You shall not take the name of the Lord in vain; Remember the Sabbath day to keep it holy)
Love your neighbor as yourself (Honor your father and mother; you shall not murder; You shall not commit adultery; you shall not steal; you shall not bear false witness; Do not covet anything that is your neighbor's).
Plus, the disciples' charge (what modern Christians call the "Great Commission") was to "Go ye therefore and teach ALL NATIONS, baptisizing them in the name of the Father, the Son, and the Holy Ghost." Whosoever wants to learn of Christ is more than welcome. There is no "secret" society, as the Gnostics tried to make. For these and other reasons (including the aforementioned Commandments), the Gnostics' works are usually cited as bogus.