Cast as a comic space opera, this is a bleak and deeply disturbing tale of how we treat what we don’t understand. To make this plausible, Aldiss created aliens whose mode of communication was far too complex for inter-species communication to be possible. He also based his aliens on the hippopotamus, large pachyderms who wallow in mud and whose excreta is an integral part of their life. And having made them near impossible to communicate with and abhorrent to ‘civilised’ people, he sets up a tale that explores the bestial nature of human beings.
Aldiss is a fine stylist. The book is dedicated to Harry Harrison and in terms of style, could well have been written by Harrison. Aldiss clearly recognized that using such a stylistic framework (comic pulp science fiction) provides the perfect contrast to the subject matter. The comic approach (although it is by no means a comedy) exposes the visceral nastiness of the humans, the ineptitude of those who have good intentions, their self-absorption, their severance from the natural world (and consequent psychoses).
It is also a novel about morality, exploring through the relationships between the characters what it means to be moral and what it means to lack or disregard them. Deeply philosophical, it posits the Gaia theory in a throwaway line, fifteen years before Lovelock’s first book. All of this in a short, pacy book. A lesser author would have given us something five times as long (probably at the behest of a publishing industry that seems to think bigger is better), and nowhere near as interesting or disturbing. This is the genre being used to best effect.