Many years ago, I collected some LaTeX templates when learning LaTeX. However, my interest in LaTeX was gone after submitting my PhD dissertation. I should have deleted these templates if they had not been so small. They would never be useful in the future, I thought.
In 2017, I started writing the book Learning R: R for Rookies . Unexpectedly, MS Word could not satisfy me with the typesetting. You know what I mean if you have experience (and pain) in writing a long book or dissertation with Word. Actually I suffered more, but I do not want to talk about it. I was sure that LaTeX could, but I would rather not use it.
Like a bolt out of the blue, I found bookdown.