World in Reverse — John Russell Fearn

Continuing their cosmic crusade among the stars, the Golden Amazon and her three companions discover a planet in another space where intelligent beings are being created, not through normal biological processes, but spontaneously, fully-grown, fashioned from the very chemicals of another planet. The mystery deepens when they discover that the synthetic race (and the planet it inhabits) is evolving backwards! Determined to solve these mysteries, the Crusaders find themselves up against the Mithons, a sadistic alien race led by a being known as the Supreme One. In the ensuing battle of science between two different universes, the Crusaders find themselves locked in a grim duel...with death the only prize for the losers! Another grand space adventure in this action-filled, long-running series!