To say that I’m not a fan of time travel stories is to understate the issue.
This is not to say that I don’t enjoy a good romp at time’s expense. Many films that use time travel can be fun. (I’m looking at you, Back to the Future.) Books, too.
But often time travel is essentially an excuse for lazy writing or lack of imagination. (Now, I’m looking at you, Star Trek.)
Science fiction has so many avenues and opportunities for literary exploration that to me time travel is usually superfluous.
All fiction is, in some way, about the time, place, and idiosyncrasies of the author. After all, the author has a point to make or the effort of making the work would not have been written. The point might be as crass as “I want to make a lot of money”—in which case, I suggest the author go out and become an accountant. I’ve been writing for decades and have yet to see much money. Or, the point might be “isn’t this scientific fact/theory/locale/time of interest really neat? Let’s examine it.”
When it comes to time travel, the point made most often has to do with using the locale to target some interesting idiosyncrasy of the present. There’s a misalignment with the states that were members of the Confederacy and the other states. Hence, what if the South had access to modern weapons during the Civil War? (The Guns of the South, Harry Turtledove.) Christian religion is on the rise. What if we could go back and witness the life and crucifixion of Jesus? (Behold the Man, Michael Moorcock.)
Novels like this are examinations of the underlying subject matter. Time travel is a narrative convenience, allowing modern sensibilities to be juxtaposed against the period under scrutiny.
However, many time travel stories involve thwarting the past or thwarting the future (The Terminator movies, Back to the Future, every Star Trek time travel story ever made.) In these stories, there is a contrived crisis that can only be solved by dealing with time traveling. While I can enjoy some of these, I don’t think much of them. It’s like eating peeps. After the first time, you might regret it or chalk it up to a learning experience. About the fifth time you’re muttering kill me to yourself.
These days, time travel stories have a huge barrier of entry for me.
That said, here are a few films and books where time travel is actually used in an interesting fashion. Part of the fun—sometimes all of the fun—of time travel fiction is the surprise the author/filmmaker gives you. Consequently, I’m not going to give much away.
Primer: There are basically two kinds of time travel stories: Stories where the past can be changed and stories where the past cannot be changed. Primer is of the former category—sort of. Primer’s conceit are two engineers that discover a means by which an individual in the time field goes back in time for the duration of exposure. The time machine, the “box”, is entered, the field is turned on, the user waits in the box a specified period of time and then turns off the field and exits at some point in the past. This means the past can be modified, occupied by different representations of the same person simultaneously, etc. Time can’t be broken—in the sense of the universe be destroyed or some such—but the individual lives of people can be severely damaged. Which is what this film is about.
Frequency: This film takes the same idea of a malleable past but locks it down. In this story, Detective John Sullivan discovers a way to talk to his dead father (Frank Sullivan) twenty years ago via a ham radio. (Just let that go.) In this kind of story, no physical objects can transit to the past. Objects can travel to the future normally. But information can be transmitted freely between present and past. John manages to tell his father how to avoid his oncoming death. Thus, he suddenly has a father again. However, there are consequences.
12 Monkeys: The past is not malleable in 12 Monkeys. Humans can go physically to the past but whatever things they do there are already accounted for. The “present” of 12 Monkeys is in our future where most of humanity lives underground in fear of a virus that has killed most of humanity. Scientists keep trying to determine how to cure the pandemic. Leftover messages and scraps of knowledge is all they have. Eventually, they manage to send James Cole to the past to uncover what these messages mean. But the cost to him is high.
Predestination: This film is based on Heinlein’s story, All You Zombies, which I think is probably the best time travel short story ever written. Essentially, this is a story about a paradox from the paradox’s point of view. I think the film is better if you read the story first, but it still stands on its own.
The Man Who Folded Himself: This novel runs the whole idea of time travel, malleable or otherwise, until the bolts fall off. TMWFH is a lovely book about Daniel, a not so lovely man who makes many, many mistakes with power he probably should not have had. The thing that is so downright good about this novel is that it is absolutely unflinching about consequences—even when Daniel is trying very hard to avoid those consequences. The novel was nominated for both a Hugo and Nebula. I think it should have won.