Bottom line up front: this was way ahead of its time. Artificial intelligence and swarm behavior, nanobots, the evolution of non-organic and non-living matter…concepts that were so far away in 1964.
I read this probably over twenty years ago and didn’t remember much about it, so I picked it back up again. What struck me more now as an adult was how advanced these ideas were, and how they were used to seed the idea that we may not find organic life. Let’s be real- a “first contact” type scenario for us is far more likely to be with a probe or drone of some sort that relies on some sort of AI/neural network. And also the idea that in much older solar systems and galaxies we may be the new kids on the block to evolve enough for space travel. The premise really hammers home two main points: life isn’t always what we expect, and we may be really late to the extrasolar/extragalactic party.
I’ve come to appreciate this even more, and really hate that I’ve kept this aside for so long.