An examination of the major heresies of the first four centuries of Christian history, explaining the mind of the Church about the errors of each heresy, commenting upon how each heresy survives in some form today, and articulating the true faith in contrast.  As the Christian faith is the greatest good on the earth, so heresy is the greatest evil in the world leading to the everlasting ruin of human persons. As the Christian faith enlightens mankind through the preaching of the Gospel, the true faith at the same time exposes error and heresy, castigating it as such in order to protect the faithful from harm and recalling those who have sadly embraced the doctrines of demons.