This is possibly the dullest interesting book I've read, or vice versa. It's seldom that it takes me this long to complete a book (even the dread Alexandria Quartet felt faster), and it could almost be said of this novel that I "couldn't pick it up".
I believe I've read some of Stapledon's work before, though I don't recall when or what - perhaps Last Men in London. In any case, I wasn't sure what to expect.
What I found was a book with an amazing scope (literally the entire lifespan of the universe, and more), and an astounding creativity. Stapledon tosses off interesting and novel ideas every few pages, including the original Dyson sphere. He postulates intriguing intelligences, species, societies, cultures, lifeforms, you name it. There's a mountain of fascinating material in here.
Unfortunately, he presents it all in a style so determinedly dry that it's hard to stay awake for the marvels. Even allowing for the period (1930's), the prose is so clinical that it begs to be treated as an academic report, to be put down in favor of something more engaging. It's a shame, because if you can keep your mind focused, there's a lot here to like.
The main story kicks off on "Other Earth", with what seems a thinly-veiled polemic against capitalist materialism. It ends somewhere in the cosmos with what seems a thinly-veiled paean to religious creationism. But neither of those impressions is really accurate, for in between is a steadfastly logical exploration of the concept of human development. This is a 'what if' story in the best way. If it reads more like a thought experiment than a story, that's not inaccurate.
'Human', in this book, means roughly 'intelligent life'. Stapledon doesn't discriminate between humans shaped like homo sapiens and symbiotic whale-crab partners. What he cares about is how they develop, and how they'll succeed. Most of them don't. This is not a warm and fuzzy YA story, and to his credit, Stapledon doesn't duck the hard questions. He makes some assumptions, and sets in motion a train of events, but there's no magic happy-ever-after. Instead, there's a genuine exploration of what could happen, and what it would mean.
'What it all means' is a central theme of the novel, and perhaps its reason for being. I found Stapledon's answer to have too strong a religious tinge for my taste, but it's clearly something he (and his narrator) thought long and hard about. Ironically, C.S. Lewis thought Stapledon's answer was "devil worship", so perhaps he hit an unhappy medium after all.
I recommend this book. It's a slow and painful read - much more of a slog than a sprint. But if you persevere, and if you manage to keep Stapledon's ideas in focus, you'll be rewarded. I wish (oh how I wished
while I was reading this) that Stapledon had been a lighter writer. He Wasn't, but his ideas are worth engaging anyway.