This book follows Fleet of Worlds but there may be books in between. Sigmund Ausfaller appears again in this book. He was a Puppeteer paranoid in earlier books. He is yanked out of known space by Nessus as a buffer or "wild" human to protect the now separate colonists. The PAK are reintroduced to the story line and the focus of the story is the avoidance of the PAK.
This is a very similar cast to the Fleet of Worlds with the exception of the PAK and Sigmund who have populated previous Niven books. The Gw'oth are a newly found, rapidly evolving species who play a large part in the changes that occur in this book.
If recollection serves me, Sigmund was an implacable foe of the Puppeteers in earlier books but he is now tempered by a wife and children. Lots of action, scary foes and interesting technology.
I recommend the book.
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This book may have been received free of charge from a publisher or a publicist. That will NEVER have a bearing on my recommendations.