Firebird by Jack McDevitt is the sixth book in McDevitt's ongoing science fiction series about far future antiquities dealer Alex Benedict and his assistant/partner/pilot Chase Kolpath. Ideally, I'd recommend reading the Alex Benedict series in order (A Talent for War, Polaris, Seeker, The Devil's Eye, Firebird) but like the other books in the series Firebird works quite well as a stand-alone book and should be fairly easy to understand whether you've read its predecessors or not.
40 years ago on Alex and Chase's home, the colony world Rimway, the famous and controversial physicist Dr. Christopher Robin mysteriously vanished from the planet, never to be seen again. When his widow dies 40 years later, Alex is commissioned to find buyers for the renowned scientist's personal items. Seeking information that could help them build interest in the items among potential buyers, Alex and Chase delve into the history of Dr. Robin, an enigmatic man whose theories on the existence and nature of alternate universes made him a figure of intense controversy, shunned by some and idolized by others, whose mysterious disappearance has made him the subject of wild speculation ever since.
The trail leads them to encounter two of Robin's other interests. One is records, some recent and others going back thousands of years, of unidentified ships appearing near human worlds and then fading into nothingness a few minutes later. The other is human interstellar ships that depart on routine faster-than-light trips and are never seen again, a rare but troubling phenomenon that has claimed numerous victims throughout humanity's thousands of years of interstellar travel- including Gabriel Benedict, Alex's uncle and Chase' former employer. They also begin to discover clues that Robin was up to something strange in the final years before his disappearance- and may have been on the verge of a discovery with implications far beyond the mystery of his own fate.
Firebird is another solid entry in the Alex Benedict series. The main story is interesting and goes in some unexpected directions, and Chase Kolpath is once again an enjoyable character and first-person narrator. Much of the story is fairly sedentary and not too far removed from a conventional mystery story, with Chase and Alex investigating Robin's past by fairly prosaic means- interviewing people who knew him, searching for records, visiting places he been- but the mystery is interesting and made these scenes satisfying for me. It also segues well into the more specifically science fictional aspects of the story that become predominant as it progresses. There are also some more fast-paced or tense bits that work well.
I especially enjoyed the part of the story where the investigation takes Benedict and Chase to the planet Villanueva, a formerly populous and advanced world that was cut off from humanity for centuries by an interstellar dust cloud that extinguished the human population but left the infrastructure and the AIs charged with running and maintaining it intact. Left to themselves, they've continued to do exactly that, keeping Villanueva's dead cities intact and running for thousands of years- and making new human settlement impossible by attacking any who land. It's quite creepy, as Alex and Chase search for clues in clean, well-maintained, still-powered cities completely devoid of human life. The way the story deals with the AIs of Villaneuva is interesting, and leads to some interesting scenes later when Alex Benedict becomes the center of a political debate on the nature of AIs and human responsibility for those left behind by the death of Villaneuva's human population.
McDevitt is good at using rather mundane elements in ways that complement the science fiction/space opera aspects of the story- the implications of AI sentience are argued about on evening talk shows, Villaneuva is dangerous to human life not because its AIs are either interested in or capable of attacking humanity but because of the hordes of pro-AI activists and amateur treasure hunters descending on the planet and getting themselves killed after it becomes a subject of media attention, and the search for the truth about Dr. Christopher Robin is at least as much about old-fashioned investigative skills as it is dangerous journeys on hostile planets or in deep space. This could be dull if it were handled poorly, but in Firebird it's effective at giving the setting a greater feeling of solidity than it would have had otherwise.
The relatively familiar, recognizable future presented in the Alex Benedict books has often been the subject of criticism, for reasons I can appreciate but don't share. It fits the larger context of the setting, where human interstellar civilization has undergone multiple dark ages in the time between the present day and the stories, so thousands of years in the future doesn't equal thousands of years of technological progress. I also think the similarity of McDevitt's setting to our own world tends to be overstated by some people, probably because of what does and doesn't get attention in the stories. For instance, there are allusions to the fact that on many human worlds one can simply forgo employment and live- and apparently live fairly well- on some sort of government stipend every citizen gets, and that this is not a rare or stigmatized choice. That implies economic productivity far beyond what we have now, as well as a profound cultural difference, but the technological underpinnings of that don't come up because there's no reason for them to..
A lot of it boils down to one's own beliefs about the future and the extent to which a setting deviating from those beliefs impairs your enjoyment of the story. (I'm not of the “life in the future will necessarily be unrecognizable to us today” school of thought. It wouldn't surprise me, but I don't consider it so self-evidently true that the contrary assumption attacks my suspension of disbelief.) Both of these things vary widely from individual to individual, so while I like it myself I can certainly understand why it's a sticking point for some.
I would definitely recommend Firebird for fans of Jack McDevitt, and for fans of science fiction with a mystery/investigative bent. If you didn't care for McDevitt style before it's not going to wow you into changing your mind, but if you've enjoyed his work in the past it's well worth reading.