This has some fascinating concepts and is unusual for involving humans only tangentially in the frame. Rather it examines two different alien races on sister planets. One, the Thalassans, from amphibian lineage, is probably the most human in its cultural development, eventually developing a totalitarian "Organic State." The Hetairans, from a feline lineage, have not families but "gangs" of related individuals. They're egalitarian in gender and anarchic in governance--not a close parallel, but they're possibly meant to play Americans to the Thalassan Soviets. The book was first drafted before 1964, given it was developed from a manuscript found after Piper's death, and you could certainly see the era's Cold War tensions reflected in the plot.
The problem is this is all tell, not show. That might not be Piper's fault at all. I know from his Fuzzy Sapiens stories the man could write. But this was developed by Michael Kurland from a draft; Piper never had a chance to create a polished, final version. One can tell the major problem with it just by flipping the pages. There's very little dialogue here because except for some vignettes interspersed throughout, this is almost entirely narrative summary of the history of the development of the two races. It might have worked better if like, for instance, Asimov's first Foundation book, it had been worked into a series of stories at key points of the histories, but that's not how it's written, so it's only intermittently interesting. It needed to either be cut and expanded accordingly--or just cut drastically into a short story focusing on the events after First Contact that forms the last chapters. There's just not enough here to make the characters come alive enough to care what happens.
