Six Volumes

Even when most Poul Anderson books in a household are packed for a house move, an Anderson fan can still remember and reassess that author's major future history series.

The three stories collected as Trader To The Stars present a character, Nicholas van Rijn, and his milieu, the Polesotechnic League, the mercantile arm of Technic civilization. Van Rijn is not young and the active phase of his career seems to have come to an end by the time of the third story.

The three stories collected as The Trouble Twisters present a younger character, David Falkayn, who, after his apprenticeship to another merchant, becomes a van Rijn employee, then leads van Rijn's first trade pioneer crew/trader team. Falkayn is successively an apprentice, a journeyman and a Master Merchant while van Rijn lurks in the background. 

Developments: a new character; his career development; two non-human trader team members.

In the novel, Satan's World, van Rijn and the trader team avert an external threat to Technic civilization.

Developments: 

now four continuing characters cooperating with each other; 

more information about Technic civilization which has been infiltrated but has not yet undergone any internal changes.

In the novel, Mirkheim, van Rijn reassembles the now disbanded team to address a crisis that becomes the beginning of the end of the League. Falkayn becomes acting CEO while van Rijn, travelling in the team's former spaceship, tries to delay the now inevitable dissolution of the League.

Developments:

chronologically the last Polesotechnic League instalment;

the climax and culmination of the combined League, van Rijn, Falkayn and trader team series;

the beginning of the transition to the next major stage of the Technic History.

The novel, The People Of The Wind, is set centuries later on Avalon, a planet jointly colonized by human beings and Ythrians led by David Falkayn. The many characters include a direct descendant of Falkayn.

Development: this novel is set during an early stage of the Imperial period.

Shortly after the events of The People Of The Wind, an Ythrian fictitiously compiles The Earth Book Of Stormgate which collects:

two Ythrian short stories set earlier than the Polesotechnic League (PL) period;

eight PL instalments set earlier than Mirkheim;

two Ythrian short stories set between Mirkheim and The People Of The Wind.

Van Rijn and the trader team reappear in previously uncollected stories on a "now it can be told" basis. We are already familiar with but now learn more about:

Ythri

Ythrians

the Ythrian Faiths

Avalon

Adzel's student days

the planet, Ivanhoe

van Rijn

the trader team

Baburites

Sandra Tamarin

Merseians

Mirkheim

Coya Conyon

the Supermetals company

the two-stage colonization of Avalon

Although they comprise less than half of the Technic History, I regard these six volumes as the peak of American future historical writing.