Found this one that I bought in 1977 and apparently hadn’t read. It’s a set of four loosely linked tales about adapted humans, with the basic premise that finding habitable earth-like planets is pretty unlikely, terraforming planets is very long-term and costly, and therefore the way to go is to manipulate humans so that they can live in radically different conditions. And yet Blish’s adapted humans think and emote just like us ordinary humans in hard SF… I found this just a little unconvincing, really. The novel dated from the mid-1950s, and yet already there is the notion that humans are outgrowing, and wearing out, their own planet.
As I read this moderately interesting novel of ideas – for that’s basically what it is, nothing plot-wise to sustain a reader’s attention here – I was struck by the progression from Olaf Stapledon, in Last and First Men, where humans modify themselves in order to colonise planets, in the sweep of a story of humanity across several billion years, to Blish in this novel, exploring a similar idea, but focusing on smaller groups of individuals in a more limited time-frame, with the similar idea of humanity ‘seeding’ other worlds with intelligent life. And then I realised what Ursula Le Guin had done, picking up the same idea in a much more sophisticated manner in her Hainish novels and stories. In those, the Hainish, in the distant past, seeded many worlds across the universe with variations on the human form; these eventually re-discover each other and form a loose association called the Ekumen, and homo sapiens here on planet Earth is merely one of the results of the Hainish seeding. And then, with her background in anthropology, she can put homo sapiens under the microscope.
It’s good to see how writers play with each other’s ideas, develop and vary them, and provide us with more food for thought in different ways. I can acknowledge Blish’s part in this sequence, and I liked the final twist at the end where the racism that had always blighted humanity’s time on Earth, re-appeared as the different human types re-connected with each other, and the ‘original’ Terrans demonstrated their innate sense of superiority once again… But ultimately Blish is too much hard science, and unconvincing would-be humans for me.