They are fairly easy to find on the internet in French, if you want to receive excellent translation (OPTA club Editor anticipation book): in three volumes:
kesrith - Kutath Son'jir ....
If not in English: The faded south which is a superb title especially when compared with that of the French translation, which is pretty simplistic and more definitive with: Sun death.
I suggest you rather faded or dying sun, which would be more authentic and in the spirit of the cycle ..
It is a cycle (a very coherent trilogy) pretty amazing, exotic, poetic enough with an atmosphere that is palpable. This is even a pseudo trilogy because these three novels are very supportive to constitute IMHO the three facets of a single text, but they are well published successively.
Key themes of this trilogy to very supportive volumes:
-The Contact between different species, diplomatic and military reports arising from these dating. As close as active, very practical and structural consequences, relating to the very nature of the species in contact, which frequently interfere with the plot and are an important part of the material of the novel.
-The Theme captured soldier and subjugated by the enemy, with the themes "corollary" of voluntary servitude or psychology of submission, even the Stockholm syndrome at a pivotal moment of intrigue ..
-Of Biospheres and foreigners permanently living (whole panel more or less exotic) resulting from biological, cultural exo contingencies.
The style is quite remarkable because it's really well written, well built, with a steady pace and a complex intrigue and entirely in shades with a lot of momentum and movement. A real pleasure to disorientation. These are stories that have the momentum but also a lot of depth because the issues are carved in a thousand ways: introspection, description, discussions ... and the reader feels the passing of time because it is the will of the author.
The reader is holding its breath all along, because of a very pregnant strangeness, also because of the large presence of the characters that play various affects the occasionally very intense and mysterious facets.
There certainly has a sense of decorum in these three very measured and weighed texts.
A great moment of science fiction altogether in what is finally better, on the theme of the conflict, contact and cultural mediation between species ...
Topics that are too often marred by ridicule and ease ...
The pitch: Two companies, including a human, large expansion areas, make contact, to find, negotiate placeholders and things do happen nor evil nor good, but the contact is objectively difficult, fatally dangerous tangent and highly anxiety-provoking for some people ...
A third species dedicated to the functions of mercenaries and simply dedicated to the war is endangered and on the verge of extinction. In this complex games this species will try to survive through the leak and a homecoming.
There is something heroic in this deliciously "pitch" because it is a nothing, epic and classic inspiration, the ancient sense of the word.
The aliens, I found them, in terms of Réguls, staggering because of their characteristics "others" who are excessively detailed with a timeliness to the relevance and exquisitely comfortable readability. In terms of Mriis (mercenaries), there is instead a clear and a soft focus, which envelop them constantly and that's disturbing but very pleasant and it contrasts sharply with the presentation of Reguls. In a way the author offers two treatments, subtly different, the theme of the Alien science fiction.
This is my favorite aliens in what I know of science fiction, I think especially to Reguls about it.
If you appreciate the cycle of Chai (among others) .. I think we can be quite sensitive to this trilogy ..