It is an interesting book that allows a person to have ONE SIN after they have been baptized. It is also found in several of the oldest Greek bibles known.
It is best classified as a pious fiction. Not even Biblical.
You can find a copy in THE LOST BOOKS OF THE BIBLE along with other fabrications.
It seems to be rather rigorist in morality, while at the same time kind of confused in Christology. At this point I will stop beause I don't know much about it.