The Technic Civilization Saga, Volume VI

Poul Anderson, Sir Dominic Flandry: The Last Knight Of Terra (Riverdale, NY, 2012).

Contents:

"The Plague of Masters" (1961), pp. 1-147;
"Hunters of the Sky Cave" (1959), pp. 149-301;
"The Warriors from Nowhere" (1954), pp. 303-337;
A Knight Of Ghosts And Shadows (1975), pp. 339-606.

My rule of thumb is that a novel is 100+ pages in length. By that criterion, Sir Dominic Flandry..., like Volume IV, Young Flandry, collects three novels. "The Warriors from Nowhere," written earlier, is much shorter and retroactively became a brief prequel or prelude to A Knight...

I divide the original Captain Flandry series into three sections:

A Tetralogy
"Tiger by the Tail" (January, 1951)
"Honorable Enemies" (May, 1951)
"The Game of Glory" (1958)
"Hunters of the Sky Cave" (1959)

A Diptych
"A Message in Secret" (1959/1961)
"The Plague of Masters" (December, 1960-January, 1961)

On Its Own
"The Warriors from Nowhere" (see above)

The Tetralogy
In "Tiger by the Tail," Flandry conquers Scothania.
In "Honorable Enemies," Flandry is referred to as the conqueror of Scothania and learns how to lie to the telepath, Aycharaych.
In the opening passage of "The Game of Glory," it is mentioned that Flandry learns how to lie to a telepath; then he visits Nyanza.
In "Hunters of the Sky Cave," Flandry has returned Home from Nyanza, is congratulated on l'affaire Nyanza and has a showdown, although not the final showdown, with Aycharaych. Flandry captures the telepath but the Merseians insist on a prisoner exchange.

Thus, these four works are a continuous sequence.

The Diptych
In "A Message in Secret," Flandry is on Altai.
In "The Plague of Masters," Flandry visits Unan Besar while returning Home from Altai.

Thus, these two works are a sequence.

I think that we should read first the tetralogy, then the diptych.