Introductions And Interstitial Material

Poul Anderson's Psychotechnic History is collected with:

"Interstitial Material by Sandra Miesel"
-Poul Anderson, The Complete Psychotechnic League, Volume 1 (Riverdale, NY, 2017), title page.

Anderson's Technic (not Psychotechnic) collection, The Long Night was published:

"With Prologue and interstitial material by Sandra Miesel"
-Poul Anderson, The Long Night (New York, 1983), p. 2, title page.

Baen Books' The Technic Civilization Saga, compiled by Hank Davis, includes the introductions that had preceded eighteen of the stories when they had appeared in three previous collections:

Trader To The Stars;
The Trouble Twisters;
The Earth Book Of Stormgate;

- but not the Prologue or interstitial material that had appeared in The Long Night.

The twelve works collected in the Earth Book span the period from the Grand Survey to the settlement of the main Avalonian continent, and thus cover the entire era of the Polesotechnic League, whereas the introductions in the Earth Book are written as if composed even later, during the aftermath of the Terran War on Avalon, thus during the period of the early Terran Empire, although Avalon is in the Domain of Ythri, not in the Empire.

The five works collected in the not altogether appropriately entitled The Long Night span the period from the Time of Troubles to the Commonalty and thus cover the entire periods of the Terran Empire, the Long Night and the Allied Planets. Thus, The Long Night itself comprises a miniature, single volume, future history, containing:

Miesel's Prologue, summarizing the Breakup, the League and the Troubles;
"The Star Plunderer," about the Founder of the Terran Empire;
interstitial material about the Empire;
"Outpost of Empire," about one planet in the Empire;
interstitial material about the Empire and the Long Night;
"A Tragedy of Errors," set during the Long Night;
interstitial material about the Long Night and the recovery;
"The Sharing of Flesh," about a rediscovery expedition during the Allied Planets period;
interstitial material about Vixen, New Vixen and rebels banished by Flandry;
"Starfog," about a Ranger of the Commonalty and the descendants of the rebels;
a brief, closing, poststitial passage ending -

"Shines the sun ne'er so bright,
"In the end must come the night." (p. 310)

- whereas the Psychotechnic History closes with a brief, poststitial passage ending:

"One chapter has ended. Humankind's saga flows on."
-Sandra Miesel IN Poul Anderson, The Complete Psychotechnic League, Volume 3 (Riverdale, NY, 2018), p. 216.

Or, as some Star Trek publicity proclaimed: "The adventure continues."