Good move...
Hi REB
"Protector" is one of my favourite "Known Space" novels. It's a toss-up between it and "Planet of Taavs". The Pak are a rather clever speculation on human origins, and it's not Niven's fault that the idea was falsified by molecular dating in the late 1960s. Likewise LeGuin's Hainish sequence of novels and stories.
Greg Benford and Steve Barnes expand on the idea in their "sequel" - "A Darker Geometry" which has the Outsiders seeding worlds in the Core deliberately, hence making the Pak for their own purposes (or Someone else's...)
Adam