When I build a book in pdf format using the bookdown::pdf_book, there are large whitespaces (see the image below) throughout the book. What would be the best approach to reduce the size of the whitespaces?
My book repository is here and the latex preamble is here
I confirm that by default in PDF document, figure will be floating and place where there is space. You can reduce size or find how to change the floating behavior and figure positioning with LaTeX.