Sufficiently Advanced Technology: the first book in the Inverse Shadows universe

A multi-planetary post-singularity society (the Confederation) desperately wants to know how to achieve transcendence into an Elder Race. Their scouts encounter Darius, a lost colony world whose inhabitants have apparently discarded the technology that brought them to the planet, in order to adopt a virtually feudal culture.

But the scouts are shocked when they discover that the controlling elite, in each of the major centres of population, exhibit abilities that defy the accepted laws of ph...