This is a booklet version of lectures that Rushdoony delivered in Australia. He demonstrates the Romans Imperial state understood, like today's humanistic state, that all of life is religious. Both Imperial Rome and the secular humanist governments of today view Christians as rival religions that threaten the very foundation of the social order.
The Romans labeled the early church fathers as atheists and irreligious because they rejected the religious social order of Rome. Though the modern state does not use this language about Christians today, it does see Christianity as a threat in the same way. The modern state seeks to force Christians into denying the Lordship of Christ over every realm--instead allowing Christians a privatized religion, but not allowing the Lordship claims over any public realm.
A good, short work.