This is an introduction for the novel.
Time travel is not, as far as we know, a literal phenomenon. We have no means to transport our bodies or minds either into the actual past nor the future. But, the subjective experience of time travel is ever present.
Humans have evolved to be able to mentally position ourselves in as many novel situations as can be imagined. This capacity is one of the primary means in which we survived our early threats (of predators as well as conditions). Our mental projections have allowed us to plan and to learn.
We plan via time travel into the future. We learn via time travel to the past.
But these systems are not foolproof. It is an unfortunate consequence of our biological adaption that some of us can get fixated on time travel, obsessing about our pasts or our futures, spending more time in those imaginary places than in our real lives, in the present, here and now.
These stories are about those kinds of experiences. Our fixation on time and our undying desire to be in a time different than our own. And ultimately, the stark fate that, no matter where we go, there we are.