This omnibus of some of Stephen Baxter's earlier novels: Raft, Timelike Infinity, Flux and Ring is great value. If you are a fan of hard SF and/or Stephen Baxter, it's well worth it.
All four are standalone novels which are loosely bound as the Xeelee sequence.
The first novel, Raft, is also Baxter's debut. As such, it is a little rough in some areas. Mainly (and in fairness, he won't be the first SF writer to suffer from this) in that the characterisation is a little weak. In this, I think it's mainly that the hero looks too perfect next to the almost uniformly gormless people he encounters (not quite, but you get my drift). The story itself is pacy and fun. The ideas it has are clever and believable (Baxter is a scientist). The people in the story are trapped in a universe where gravitational force is much higher than it is here. This is handled in an interesting way. Great stuff.
Timelike Infinity follows on, but is, as I said, standalone. This one is concerned with cause and effect and considers the future of the human race and its subjugation and how these things happening. Potentially head mangling, but handled well. Characterisation slightly better in this!
Flux is my favourite for the ideas in it. It features a group of artificially engineered nano-scale humans that live below the surface of a neutron star. They are part of the fight the humans are engaged with against the mysterious Xeelee. This is in the background, though, given the smaller scale it's not necessary to know the rest of the story. This is, ironically, the one I found most convincing in its characterisation, given that the people aren't old-style humans! The story starts off looking like it's about saving the main character's family, but moves on to encompass their world and beyond. Great stuff.
Ring is the final book in this sequence. It seeks to wrap things up. It's even more ambitious than the other 3, great stuff. There are two plots, running parallel in this novel - following an AI left in the sun to examine it, and that of a "generation ship" with a number of different factions. Through these the novel seeks to wrap up the story of the Xeelee - the other novels have hinted at there being a wider conflict between the Xeelee and humans; in this we find what it is that the Xeelee have been up to all the time and learn some unfortunate truths (for the humans!) about what they have been involved with and what it means for the human race (and indeed, all life). There are more scientific musings on quantum physics and the nature of observable reality.
Apart from the sometimes weak characterisation, the one other criticism of this group of novels is that there is (much in the tradition of hard SF) a lot of info-dumping. I didn't mind, but watch out if you find this objectionable.
As I say, it's good value, and in spite of the criticisms (weak characters and info-dumping) it's worth its 5 stars. The stories are interesting and rollicking good fun.
Recommended!
Incidentally, if you like these novels,
Vacuum Diagrams is an anthology of short stories set in the same universe.