This is the second edition of Clarke's meditation on the likely consequences of the potential and probable scientific and technological breakthroughs during the course of the 20th and 21st centuries. The study is predicated on a key insight: the fact that certain scientific and technological breakthroughs could never have been predicted by earlier thinkers. Whereas the internal combustion engine would have been comprehensible to Galileo or the ancient Greeks, the simplest electronic device operates on principles that were completely unknown to such classical thinkers. For Clarke, the science of Maxwell, Einstein and Heisenberg has enabled us to understand of the fundamental forces that govern the universe, and as a result the anything that is scientifically possible, will become technologically possible for human civilisation in just a few generations.
Some of the ideas contained in the survey that follows look quaint and even embarrassing to the reader in the early 21st century. Particularly cringe worthy is the chapter almost totally dedicated to the hovercraft and the revolutionary implications that it will have. Clarke seems to fall for a pitfall of many futurists: just because a technologcal innovation becomes possible it does not follow that it will see widespread adoption, as it may not fit into any social or economic niche (the videophone exists, but doesn't fit human needs well enough for general adoption). In other areas Clarke is insightful and prescient. His vision of a human-colonised galaxy as a scattering of isolated ant hives is both chilling and inspiring. In particular, his thoughts on satellite communications were visionary for his time - Clarke invented the concept of the geo-stationary satellite some years earlier. He even manages to glimpse the eventual rise of the internet, although he saw it in terms of a global satellite televisual network. His even bolder claims, about anti-gravity for example, have yet to be confirmed or falsified by progress.
All in all, the book is well worth a read as a an idiosyncratic vision of our future technological development. Some of what the book predicts will never come to pass, some of it already has, and much still might.