Tau Zero. Otherwise, "Pride" would have been simply an independent story of space exploration. I suppose that any number of stories set in space could be linked into a radial series if their texts were to incorporate such common background references.
The spaceship Anna Lovinda has two purposes:
to test the Bussard drive that might be used for interstellar journeys - and is in Tau Zero;
to investigate "Nemesis, long-unseen companion of Sol..." (p. 5), a "brown dwarf" (intermediate in mass between a star and a planet), and even to land smaller craft on some of its planet-sized satellites.
Nemesis is so called because it is the body whose passage through the Oort cloud disturbs the comets so that some fall towards Sol with catastrophic consequences if they hit the inhabited inner planet. James Blish's unfinished novel King Log features Beta Solis, the long unseen white dwarf companion of Sol, and its planets, including one that is inhabited.
My Anderson agenda has become:
to finish rereading "Pride" because of its connection to Tau Zero and because it is interesting in itself;
to return to rereading the fascinating World Without Stars, which is a companion volume to Tau Zero since both are transgalactic in scope;
to reread "Call Me Joe" because it is a further Anderson work set on Jupiter;
maybe to reread "A Bicycle Built For Brew" and one or two other early works with common backgrounds.
Rereading just became more complicated.