I read a fair amount of PA in the 80s and there were things I loved about his work and things that made me cringe. Reading Omnivore brought my love/hate memories into sharp focus. Published in 1968, Omnivore takes place in a not so distant future, but one with space travel and human colonization of distant planets. While a little disjointed at first, the story soon sorts itself out. A special agent, Subble, has an assignment to investigate the three survivors of an expedition on the planet Nacre, who are now back on Earth. Subble visits all three in turn, and from each one gets a part of the story of what happened on Nacre.
PA performs some fascinating world building here; Nacre is a planet populated primarily by the 'third kingdom' of life, namely fungus. Yet, the life on Nacre is not your typical slime molds! Nacre has lots of mushrooms and such, but it also evolved analogies to living creatures, such as herbivores who munch on various forms of fungus, omnivores who prey on herbivores and local 'plant' life, and finally, carnivores who prey on the omnivores (get the title yet?). The three person team of Veg (his nickname as he is a vegetarian), Aquilon, a beauty (of course) and Cal, a brilliant but partially disabled man. The three are on a mapping/exploring expedition on Nacre, cruising around with a high-tech tractor when they encounter a 'manta'-- one of the apex predators of the planet. The mantas are fascinating aliens and PA is exceptional here regarding them. After trying to outrun a manta, the tractor breaks down and the small group is stranded miles from home base. The stories they tell the agent fill in the blanks regarding what happened next. Subble himself is a great character; the agents have their memories 'wiped' after each mission, just leaving their training behind. All agents are almost supermen, with a variety of enhancements and skills.
Now for why PA can make me cringe, which is here in spades. While I realize social norms differed regarding women back 'in the day', and often older science fiction (and other genres) are quite sexist, PA manages to be both sexist and pervy at the same time. This, for lack of a better word, is his 'skeezy' aspect, and in Omnivore, the skeeze centers on Aquilon. She is the center of a strange 'love triangle' with Veg and Cal; it seems she really needs a man to feel complete, but cannot choose between the two men for fear of hurting the one left out. Her curves and body are described in detail almost every time we encounter her, and she literally throws herself on the agent when they first meet; her 'vamp' routine. She is an artist (painter) and her role on the expedition was to paint the local fungus-life. She could have been a strong female lead, but instead is a needy sexual object. There really is no rationale for his skeeze here; it does nothing for the plot or story in general.
So, on the one hand we have some exceptional world building and great aliens, along with some mystery regarding the future of Earth as a result of encountering Nacre; really classic science fiction tropes done very well here! On the other hand, we have PA with all his skeeze regarding female characters. PA is quite erudite, and Omnivore fairly drips with references/quotes of Shakespeare, classic English poets and so forth. His prose is lively and often funny, and the action scenes are intense. The overall story is amazing, including his explication of the Third Kingdom. Yet, all of this is really dragged down by his skeeze. This could have been a 4 or even 5 star read, but as it stands, the best I can give it is a 3.