I've now finished
The Uplift War, and it's a great end to the first part of the series.
It takes place right after the events of the previous book, but on another planet called Garth. Garth is a colony of Earth, with both humans and neo-chimps. An avian-like alien race called the Gubru has decided to invade Garth and hold the Terrans hostage in exchange for information about the ancient spaceships and relics found by the dolphin crewed spaceship Streaker in the previous book
Startide Rising.
The book follows the humans, chimps, and a couple of friendly ETs and their fight against the invading Gubru. I thought the characters of the chimps and ETs were very well done. I thought the depictions of the neo-chimps, mostly alone, conducting an underground resistance to the Gubru were great (and they even make a joke about guerilla warfare

). Plenty of action and character development both, and even though the chimps are similar to humans they are different in some fundamental ways, and those differences are well handled and add considerably to the story.
I liked all three books in this series quite a bit, I think it's one of the best series I've read in a while. This last book is my favorite, but all three are good.
I've now started the second series of three books. These are written about 10 years after the first three. The first one in this set is
Brightness Reef. It's a little slow getting started, but I'm only about 15% of the way in.