Lords of the Psychon — Daniel F. Galouye

CITY OF FORCE
Huge prisms, obelisks, cubes, cylinders, rhombohedrons, domes ,pyramids shimmered with glowing colors, coruscating essence, blinding radiance...

HERE WERE THE LORDS OF THE PSYCHON!
And Horror Day was fast approaching, the dreadful day when Earth was held inescapably in a grid of luminescent, evil energy, the day when Earth might be torn into another universe!

A little band of ragged men, the pitiful remnant of the Army and Navy of the United States was all that stood between this unimaginable fate and the "Lords of the Psychon."