And your reasons for thinking it is crap are ... ?
Just saying so doesn't make it so. History is written by the victorious, not necessarily the purveyors of literal truth.
***And your reasons for thinking it is crap are ... ? **
Learning.
If I step in dog $#it I dont have to look at it and ask, "Is it bubble gum or chocolate?" And I don't have to stick my finger in it to find out.
The book you mentioned is CRAP.
Get wise! Get educated! Find a good library and do your own research of the Gnostics and other weird groups of that time.
Read Eusebius. Augustine. and other authors who had first hand knowlege of these groups. Go to a Bible book store and look for books opposing this crap you are fostering off on us.