The Book Of D'ni by Rand Miller

A richly detailed cultural and historical portrait of an ancient, vanished civilization, tracing its origins, language, arts, philosophy, and the development of a unique technology that links worlds; the narrative covers the society’s literary and engineering achievements, the internal conflicts and moral choices that led to its decline and catastrophic fall, and the attempts by later explorers and survivors to understand, preserve, and reckon with the legacy left behind.

The 17008th greatest book of all time