Earth Divided — John Russell Fearn

Centuries had passed by on Earth since the Golden Amazon, Abna and Viona -- the original Cosmic Crusaders -- had set off on the interstellar quest. Their adventures had led them to travel in time, and their breaking of the light-barrier had also added to the time discrepancy between themselves and the Earth they had left. The science on Earth had advanced, not least because of the foundations the Crusaders themselves had laid. Now that advanced science reaches out to the depths of the galaxy, and snatches them back to a divided Earth. One half is in thrall to the 'Pagans,' scientific barbarians, who are seeking to overwhelm the remaining 'Normals' … unless the Crusaders can prevent the spread of scientific barbarism!