As a writer www.donnalanenelson.com when I read, I often am aware of the techniques used by the author of whatever book I'm involved in.
As a mystery writer who uses history as part of each book, I know that no matter how much I loved the research, no matter how much I want to share what I found, there is always a no-no.
What is that?
Using the research out of the joy of finding even though it detracts from the story. The last thing a writer wants is for a reader to feel they have to read this or that fact so the author won't feel research time was wasted or is showing off the knowledge.
Right now I'm reading The Dandelion Years, which is a story within a story. The historical part is about Bletchley Park, the UK decoding centre during WWII.
I had never heard of it, so the trusty iPad came out. Nothing like researching some else's research on a lazy Saturday morning.
Yup it was a real place. And then I saw how the author snuck in a bit of her research without it being apparent.
She has a couple who both work at Bletchley Park meet on a train when the man is doing a crossword puzzle. The woman offers to help.
Aha!!!! Seems some of the recruits for Bletchley Park were winners of crossword puzzle contest organized by a newspaper at the government's request.
The author doesn't use the contest, but I can imagine her sitting at her laptop and thinking, "Aha, that's a skill the decoders needed. I can use it in a different way," and she puts her characters on the train and whips out the crossword.
As writers strange things, often inexplicable, trigger what we write. And I have no idea if my theory about how the author really decided to add that scene on the train was correct or not, but I am betting it is.
I do know that even when as writers we don't explain something, the result of the research adds depth because there is a certain truth behind it.