Connections

Although any fiction stands or falls by the quality of its writing and ideas, an additional pleasure in series fiction is consistency between details in successive installments, even more so when the series is a multiply-authored shared universe. My current interest is the three Man-Kzin Wars stories written by Poul Anderson but it is impossible not to notice connections between these works and some of the other contributions to the series.

The Man-Kzin Wars, or Wars Against Men, occur in a two century period of Larry Niven's Known Space future history, in which:

the Thrintun ruled the galaxy a billion years before men or kzinti;
one Thrint survived in stasis and others might;
men won their first war against the kzinti because they bought the hyperdrive from another race;
kzinti acquired the hyperdrive and fought more wars against men but always lost because they attacked before they were ready.

Anderson's first Man-Kzin story reveals that a human traitor called Markham gave the kzinti the hyperdrive. Two stories co-written by JE Pournelle and SM Stirling feature both the Thrintun and a younger Markham. Thus, four writers' works interconnect.

Markham, not created by Niven, performs a role implied by Niven's texts and, as far as I know so far, is killed in his first published appearance but this does not prevent him from re-appearing in two later-written works set earlier. In Anderson's second story, Robert Saxtorph visits Harold's Terran Bar which I suspect was introduced by Pournelle and/or Stirling.

Niven adapted a Known Space story as a Star Trek animated episode, thus importing Thrintun and kzinti into the Star Trek universe, and Alan Dean Foster adapted that animated episode back into prose short story form but within the Star Trek universe. Thus:

three works;
two authors;
two media;
two fictional universes.