Niven's Collaborations

Larry Niven has collaborated with several other sf writers and franchised one period of his future history to several more. I have ordered from the public library three of Niven's works, each a collaboration with a different other author:

the first part of an sf diptych;
the second part of a fantasy diptych;
the third part of a sf trilogy which is also part of a future history series.

This gets complicated. Fans who have kept up with Niven over the years should recognize the works in question from these descriptions.

Years ago, there was one Ringworld novel in which Louis Wu and his crew visited the Fleet of Worlds en route to the Ringworld. Now, there is a Fleet of Worlds Trilogy and a Ringworld Tetralogy!

On the Poul Anderson Appreciation blog, I have just listed several fictional accounts of visits to Hell, including Inferno and Escape From Hell by Larry Niven and Jerry Pournelle, but have yet to read Escape... so it should be no surprise that that is the second item listed above.

The Ringworld, an inhabited ring encircling a planet, is an artifact bigger than a planet. The Shipstar, an inhabited bowl partially enclosing a star, is an even bigger artifact. I have yet to read about the latter.