While doing research for the piece I discovered that Maynard Smith was a fan of proto-transhumanist science-fiction author Olaf Stapledon, particulary his 1930 novel Last and First Men. Stapledon was also influential for Arthur C. Clarke (apparently Maynard Smith and Clarke read the exact same book from the same library!), but where Clarke took inspiration for his fictional writing, Maynard Smith applied it to his science and politics. Here's a quote from Maynard Smith from a 2000 interview by Natural History:
Possibly most influential in making me interested in genetics and in evolution was a strange book by a man called Olaf Stapledon, Last and First Men. It's a history of the next--oh, I don't know--100 million years of human history. It's not terribly well written, but the book's thesis is that there will be a succession of human civilizations that collapse. And it isn't until human beings deliberately change their own constitution to make themselves less aggressive and more friendly that a stable civilization can be made. Although I no longer believe that the only path to human betterment is to change our genes, I was really persuaded by the argument at the time.