Kinds Of Series

Poul Anderson's Time Patrol series was originally complete as four short stories with a single central character, Manson Everard. The series had a beginning, Everard's recruitment to the Patrol, and a culmination, his reversal of a temporal change caused by a group of time criminals, the Neldorians. Like all sf of its period, the stories were published in a magazine before being collected.

Over a decade later, the series began to be extended:

before long, the stories were first published in books, not in magazines;

new stories were of different lengths, some even shorter than the original four but also some short novels, and were of increasing complexity;

Everard was always present although not always as the central character;

the Neldorians were superseded by a more sophisticated group of time criminals, the Exaltationists;

there is one long novel, The Shield Of Time, although it comprises three lengthy, interconnected narratives;

The Shield Of Time introduces a new kind of temporal change to be counteracted by the Patrol and reveals the Patrol's real purpose;

the series ends with a short story that was also Anderson's contribution to an original anthology on the Knights Templar;

thus, although The Shield Of Time had presented a second and greater culmination, it was not the concluding instalment and the series could have been continued further;

Everard, recruited at the age of thirty and benefiting from Patrol longevity, had lived in the same New York apartment from 1954 to 1990 but would soon have had to move elsewhen.

SM Stirling's Emberverse is a different kind of series, a long sequence of novels describing three generations of protagonists in an alternative history - and there are also short stories with which I am as yet unfamiliar.