Time Travel, Abstract And Concrete

"Time travel" means several things that are simply different.

Would a time traveller stranded in a pre-industrial period be able to use his modern knowledge to survive and thrive back then? And would he be able to change the course of history? These are not the same question. Twain answers the first, implausibly, but not the second.

In a single continuous timeline, how can causality violations be prevented if there are time travellers and can causality be circular?

How would a time traveller from our period cope with future societies and incidentally what would such societies be like? (That second question is the subject-matter of much sf in any case.)

I have just proofread a novel that addresses the Twain and changing history questions and am now reading a new novel that addresses the preservation of consistency question. They are not only different narratives but also completely different kinds of narratives with "temporal displacement" or "time travel" as an extremely abstract link.

Twain classically addressed the Twain question.

Wells classically addressed the time traveller in a future society question.

Ward Moore classically addressed the changing history question.

Before that, de Camp classically combined the Twain and changing history questions.

Heinlein classically addressed circular causality and the preservation of consistency.

The main point here, of course, is that Poul Anderson addressed all these questions in different works:

the Twain question in "The Little Monster" and "The Man Who Came Early";

the changing history question in the Time Patrol series;

circular causality and the preservation of continuity in The Corridors of Time, There Will Be Time and The Dancer from Atlantis;

time travellers in future societies in "Welcome," "Time Heals" and "Flight to Forever."

Poul Anderson is a culmination, arguably, but that does not prevent more recent authors, like Audrey Nifenneger and Kate Mascarenhas, from finding completely new angles.