Mission of Gravity

I rarely delve into older science fiction, and I'm often rather unimpressed when I do - while there are often some interesting ideas in there, the characters and plots tend towards the flakey and unbelievable (well, more so than modern scifi). Mission of Gravity, written by Hal Clements in 1954, was a refreshing change. It deals with some interesting ideas (mostly, aliens that are basically intelligent centipedes, and a planet with huge gravity that is rotating very quickly which has lots of interesting physical effects), but the characters are also quite reasonable and not ridiculous. The plot wanders a bit (it was written to be serialised in magazines, so it's rather episodic), but retains a vague overall arc and comes together surprisingly well at the end. Overall, it was quite an enjoyable read, even though parts of it read a bit like a high school science lesson.