This is another one of Cherryh's first-contact type novels, and I think it's the thing she does best, really. It involves a lone human somehow lost in alien space who manages to sneak abord a Hani merchant ship, and how his presence upsets the delicate balance of power there. It's serious without being too oppressive, and it is without question the best of the series. I've read the other three, and really you can take those or leave them--the book is complete enough in itself. (With the others, I kind of feel myself playing the Star Trek 5/Aliens 3 game--if I didn't like it, it didn't happen. Trek 5? Nope. Went from 4 straight to 6....)
I highly reccommend this book. It's typical Cherryh, in that you'll have to wait for your gratification until the very very end--but then, it's always worth it.
This is a whole new galaxy far more complex than you can ever imagine, with so many languages, behavior, norms, etc. interacting with each other - a very realistic vision of what would it be like to live in the very hub of an intergalactic enterprise. One would wonder how Ms. Cherryh came up with such alien-sounding names and all. And what is more, the whole world is quite different from what we are already familiar with. For instance, the Chanur crew are very muscular, sport mustaches and breads, and wear only trousers below their bare-chested torsos, but they are actually FEMALES! And what's more, humans are very scarce in this part of the boundless outer space. So prepare yourself for the great oydessy into the unkown!