I think this was Mary Gentle's first published novel. It's a
noticeably weaker work than her later "Ash" series, but takes itself
more seriously than "Grunts." The content is similar in feel to
Cherryh's "Foreigner." If you enjoy Cherryh in general, or
"Foreigner" in particular, I think you'll like this.
The plot follows an envoy from Earth to a barbarian world. Over time,
she discovers that the aliens are not as primitive as she'd thought.
The contrast is nicely drawn between her early self-congratulation for
not treating these primitives as animals and her later realization
that they are at least as advanced as humans.
The big plot twist---the enemy trying to kill her through much of the
books---seemed obvious. I've had others tell me it's not, so this may
be a matter of the reader's paranoia.