Caliban's War, Abaddon's Gate, Cibola Burn, Nemesis Games and Babylon's Ashes are the sequels to Leviathan Wakes (reviewed here on 23 May) in The Expanse series. My conclusions about that book included the following:
The writing is of a high standard. The environments in which the story takes place are well thought through and the writing conveys the atmosphere of the various places strongly. The main characters seem very real and both have significant flaws, which makes identifying with either of them a bit more difficult than usual. In parallel with this, the plot contains some real dilemmas, with strong issues of law and morality prompting intense arguments. This is very much SF for adults...
Caliban's War continues the story of James Holden and his crew aboard the good ship Rocinante. Eighteen months have passed since the events of Leviathan Wakes, during which time they have worked for the Outer Planets Alliance. However, the threat of the dangerous protomolecule, suppressed at the end of the last volume, is beginning to re-emerge in the form of deadly non-human combat troops. There is much about Solar System politics, which are teetering on the brink of outright war, plus on a smaller scale the search for a missing young girl. This is as readable as Leviathan Wakes, but is a little disappointing in its relative lack of innovation and dramatic tension: it is really just more of the same.
That cannot be said of Abaddon's Gate, which changes up a few gears. The alien protomolecule, which had been crashed into Venus, had since launched a vast, mysterious ring-like structure into position outside the orbit of Uranus. Spacecraft from Earth, Mars and the OPA were in close attendance, with war always likely to break out over what to do about the structure. James Holden and company are in the thick of the action as usual, in their attempts to discover the nature and purpose of the structure, with help from a surprising source. Very gripping, and about as good as SF gets.
Cibola Burn continues the story of the alien structure and the new worlds which it provides access to. The focus is on one of these 1,300 worlds, claimed by Mars but immediately settled by OPA miners, leading to a conflict in which blood begins to be spilled. James Holden is sent in to try to resolve the problem, but meanwhile among the ancient ruins and wrecks of the long-dead civilisation who originally settled the planet, something seems to be stirring… This is my favourite volume so far, due to the gripping alien interventions.
Nemisis Games takes a different track: For once, Rocinante is not at the centre of the story as she is in dock at Tycho Station for several months undergoing rebuilding after the major damage suffered in the last volume. Her crew splits up, with only James Holden staying at Tycho. Alex the pilot heads home to Mars, to meet up with old acquaintances; Amos the lethal engineer also goes home to Earth (Baltimore to be precise); and Naomi the executive officer disappears among the Outer Planets on a mission concerned with her secret past. We learn far more about the crew and their histories, adding more depth to the characterisation. In the middle of the story a devastating event occurs which changes everything, for everybody, with the Rocinante's crew desperately fighting for survival in their struggle to get back together again.
Babylon's Ashes continues the story from the previous volume, concentrating on the political and military in-fighting which followed the attack on Earth. The Free Navy which had broken away from the Outer Planets becomes a major player in the Solar System, controlling the access to the 1,300 worlds beyond the Medina Gate. The action boils down to the vendetta between Jim Holden and the leader of the Free Navy, Marco Inaros. The end of this volume sees a possible solution of sorts to the conflicting priorities of the various groups within the Solar System. Clearly, there is much more that could be written about the new worlds on which humanity is settling – and the potential dangers still existing from the ancient civilisation, plus whatever force destroyed it.
Persepolis Rising is the seventh volume of the series, and marks a major change in that the story jumps thirty years into the future. The solar system has achieved political stability with the inner planets and the Belters sharing responsibility for managing the development of the 1,300 worlds accessed via the alien gates. However, one of those worlds - Laconia - has cut itself off from the rest of humanity since it was occupied by a renegade part of the Martian Navy, and no-one knows what is going on there. Until the Laconian government abruptly makes contact again, with an ultimatum backed by devastating evidence that the technology of the aliens did not die with them. The crew of the Rocinante have been pursuing their usual freelance transport service, but some retirements are in prospect until the Laconian crisis breaks, and James Holden is in trouble and far from safety. This volume ends on a real cliff-hanger.
Tiamat’s Wrath is, for now, the last of the series (another volume titled Leviathan Falls is scheduled for release in autumn 2021). This starts some months after the previous book finishes, with the Rocinante team dispersed and most of them fighting guerilla actions against the overwhelming power of the alien technology fielded by Laconia. Another plot thread is set on Laconia itself, where the powerful inner circle around the immortal High Consul Winston Duarte is scheming and manoeuvring for advantage. The story is a good blend of action and politics, with the characterisation as strong as ever, and the continuing story introduces a new element; there are signs that a second alien race - the one which killed off the first one billlions of years ago - is beginning to wake up to the presence of humanity, and not in a friendly way.
The Expanse series is a major achievement (literally - at 4,000+ pages so far!) which deserves a prominent place in any SF hall of fame. I await the next phase with great interest.