In the 1980s, I read part of a novel that was written by a real futurist, highlighting what technologies might actually exist about one hundred years in the future. Before I forgot the author's name, I remember having seen him interviewed about space exploration possibilities on PBS's NOVA or a similar television program.
The book began with the arrival of the main character on Earth, having come from somewhere else in the solar system. Each chapter of the story highlighted at least one technological development that might have occurred by the time the book took place. Unfortunately, I cannot remember very much about the proposed technologies. There was some kind of underground train, but I don't recall what (apart from its high speed) made it distinctive compared with current subways. There was also a supersonic airplane, with variable-geometry wings; instead of two wings that both swept back for supersonic flight, there was one that just rotated (one end going forward, one end back).
I never finished the book, and I suspect that, since I don't recall it including many computing or telecommunications developments, it would probably be horribly dated only thirty-some years later. However, I am a bit curious about it still and would like to find it again.