A new novel in the Known Space universe, “Fleet of Worlds” fills in some gaps in the story of the Puppeteers and the migration of their worlds (the “Fleet of Worlds”). It tells the previously unknown story of a society of humans living with the Puppeteers without knowledge of their heritage. The Puppeteers have some deep, dark secrets revealed. There are some excellent descriptions of Puppeteer society. We are also introduced to a younger Nessus, the Puppeteer featured in Ringworld.
It is a good story, and long awaited for any fan of Known Space. Unlike the third and fourth Ringworld novels, it really manages to capture the tone of the main Known Space novels. I hadn’t realized how much I missed the environment. Note, though, that you you will have a hard time following without at least having read Crashlander or Neutron Star (Crashlander reprints all the stories from Neutron Star).