The first book is by Cherryh. The next seven are collaborations with several other authors, edited by Cherryh, but I find them remarkably consistent in style in quality despite that.
Sometimes I suspect that Caroline Cherryh did this series just to prove that she doesn't need a high-tech context to write a gripping novel.
The humans found the world of Merovin and colonized it before they realized that it was inside the territory of the alien sharr. At the request of the sharr, they asked the colonists to leave. Some of them didn't want to leave, so the human government came in and took them out by force. Still some remained in hiding.
Finally the humans gave up on the remnant and told the sharr, they're all yours. The sharr proceeded with a pogrom called The Scouring, and went away.
But a few pesky humans survived the Scouring as well. Now it is a few hundred years later. The population is growing, but everyone is terrified that the sharr will return. Technology is strictly limited to avoid anything that might be detected by off-planet monitors.
I found these books tightly plotted and very hard to put down. Religion and politics are intertwined. Everyone on the planet seems to enjoy intrigue. And at the center of it is an upstairs-downstairs liaison with real charm and depth.
Altair Jones is a case-hardened 17-year-old canal rat. She makes a scant living poling cargo and passengers around the canals of Merovingen, the largest city on Merovin, a drowned and sinking city where the social classes are ranked by how far they are above the polluted waters of the Det River.
One night a body is thrown off a bridge and, against all her better judgement, she fishes Tom Mondragon out of the canal and saves his life. Mondragon is a spy who moves in the upper ranks of society and is basically just an endless source of trouble, but he loves Jones. They come from different worlds, yet each sees the essential humanity of the other.
On a practical level, Mondragon often benefits from Jones's canaler contacts and her hard-headed sense, while Jones finds Mondragon's contacts useful in promoting the causes of the common people that keep the society glued together.
From what I've heard, no more books are expected in this series. I think this is a real shame. I'd really like to see more of them. Not only is it a great story with a lot of potential, but it's a great example of ensemble writing that works.