I'm currently reading an amazing, if unsettling, book called "Stolen Focus," by Johann Hari. It's all about the ways modern life robs us of our attention, from maliciously engineered social-media apps to our collective obsession with overwork.
The book's chapters are split up according to the 12 causes Hari sees as stealing our focus, and the author frequently jumps between telling stories and presenting evidence of his points.
Throughout the book, Hari uses a writerly trick that I remember first learning in college, in a memoir writing class taught by author and screenwriter James McBride. It's the transition between present, past, and what we can call "deep past."
The present is now. The story presently being told.
The past is yesterday, last week, last month. A story that happened a little while ago.
The deep past is years ago. A different time entirely. Childhood or ancient history.
Whenever you're telling a long story—one that weaves together plot lines, information, and context from several time periods—you'll have no choice but to dance between these three realms.
So how do you do it without giving the reader whiplash? Here's how Hari does it.
Do you see it? Here's another example.
Here's a third, just for good measure.
Phrases like, "This made me remember," "This made me think of," and "I kept thinking about" all create a bridge between the present, past, and deep past. Another great one: "Suddenly, I was [IN A DIFFERENT TIME OF LIFE] again" (e.g. Suddenly, I was 10 years old again.)
Now, sometimes your story stays put in one of the three time periods, like if something crazy happened on your way home. That's fine. You don't need to go back to your childhood to relay the events that happened 15 minutes ago.
But any time you need to jump between the present, past, and deep past, because you're dealing with bigger themes and making larger points, you'll need to find a way to time travel without creating too much turbulence.
Done well, it's almost like magic. Your reader will be transported somewhere new and utterly fail to realize how you got them there.