The Crack in Space
The book, like much 1960's sci-fi, deals with space travel, alternate histories, and other themes that were then de rigeur. There are elements of Planet of the Apes, Soylent Green, etc, etc. Even a little free-love thrown in via a giant floating space-brothel.
The story was passable, though perhaps a little predictable. There were some fun characters thrown in there, and a couple unique twists on the above themes.
On the negative side, there were a few things that broke the immersion (over-focusing on racism themes, characters focused on trivialities in the face of massive-scale events, etc).
A highlight for me though, was looking at the then-forward looking view of the future and where it got it wrong. e.g. He foresaw the global nature of satellite TV broadcasts (then a very new thing), but had the character getting up to turn the channel knob on the TV. Or he saw dynamically updated, animated e-newspapers, but they were still distributed the same way and followed the same biz model.
In any case, it was this stuff that gave me pause to think about our own present-day futurism and where we might be getting it wrong.
The Crack in Space