"Time Travel"

"Time travel" means many things. Decades ago, a guy saw me reading what I told him was a time travel novel and he thought that it must be about a group of people who had travelled into a past period and then encountered some difficulties in returning to their present! (He must have go that from somewhere.) "All" time travel books were like this... I tried to explain the concept of causality violation which apparently he had never heard of. 

Some Kinds of "Time Travel"

(i) There is a curious sub-sub-genre of juvenile fantasy novels by English women writers whose protagonists are transported back and forth between their present and a particular past period. (See The Time Travel Archives.)

(ii) Circular causality paradox narratives, perfected by Robert Heinlein and Poul Anderson.

(iii) Narratives about time travelling organizations. The only one that I know of that makes any sense, although it remains extremely paradoxical, is Poul Anderson's Time Patrol series.

(iv) Personal relationships of time travellers:

Bid Time Return by Richard Matheson

The Time Traveller's Wife by Audrey Niffenegger 

(v) Travellers exploring the future:

The Time Machine by HG Wells

"Flight to Forever" by Poul Anderson

"Welcome" by Anderson

"Time Heals" by Anderson

(vi) Characters transported into a past period when they either make some changes or fail to:

A Connecticut Yankee In King Arthur's Court by Mark Twain

Lest Darkness Fall by L. Sprague de Camp

Bring The Jubilee by Ward Moore

"The Man Who Came Early" by Anderson

"The Little Monster" by Anderson

and a current series -

Make The Darkness Light by SM Stirling

I. To Turn The Tide

II. The Winds Of Fate

III. TBA

Stirling's series title seems to follow from de Camp's novel title. Stirling's characters are time travellers by design, not by accident. They have read the sf. They know what to take with them into the past and how to conduct themselves then - insofar as anyone can. This is not Anderson's Time Patrol. These are travellers who do change history for the better - so far.

Forward march.