A good start to what is a surprisingly long series, with ti turns out many fillers written in-between the standard two trilogies. Book 2 was I think my favourite, again unusual in trilogies - that was probably 4*+but dragged down buy the other two which weren't quite as clever. The universe is nicely imagines - a deep time expansion of humanity leads to much of the foundations of human history being lost. Earth is still known, but not visited, and thousands of years of history have enveloped communities and technologies. One of the enduring myths is that of The Fleet, an earth based squadron of impressive spaceships nobly fighting the just cause. But the technology they used is long sicne forgotten along with much else.

Boss, as she prefers to be known, is a independent minded historian and technology buff. She makes a career out of "diving" wrecks. Mostly for her own amusement and interest, but also as a job taking tourists to see unusual experiences. She finds a rare, unrecorded wreck, well ff the beaten paths which contains an strange weak power signal. She realises this is particularly unusual - and at the same time slightly familiar - and pulls together a team to explore further.

That mission spurs her to investigate further occurrences of the same technology and in the next book she encounters a working Dignity Vessel. Their crew have been thrown out of time by a malfunctioning device. Book two is split between the Boss investigating a fraught location for the first time and Coop, the ship's captain, trying to discover where and when he is. The contrasting viewpoints work very well together.

By the third they've teamed up, to look for ways to help each other - prevent the Empire's local dominance and try to create conditions for Coop and his 500 people to get home. Instead there's a lot of interspersed action from the team members from the 1st dive, throwing history in awkward chunks between the narrative. It doesn't really work, although the story is good.

It's not gripping, but it is interesting. To me the biggest flaw was this repeated reliance on a 'genetic marker' for dimensional stability. Which I suppose might be engineered to be sort of possible but only because we don't have dimensional physics so don't know what it involves. It doesn't sound plausible to anyone who understands protein structure. The motivations are all pretty linear, and the politics likewise. I think it works well at the close focus level of exploring t he wrecks and bases, but is less good as a wider space opera. I may well read the rest at some stage though. ( )