Some of my students in Math 497C wanted me to divide my lecture notes into individual printouts, one for each lecture. It is obviously a good idea to do that, but I had never tried it before because there is not an easy way to carry it out with pure TeX.
However a little research led me to the free utility pdfSAM, which “splits and merges” (SAM) pdf files. In particular, it can split up a PDF file into sub-files according to the PDF bookmarks in the original file – and these, in turn, can be auto-generated from the book manuscript using the package “hyperref”.
The upshot of all of this is that I can supply this link to a directory that contains individual files for all the sections of the book – and I can update these in a seamless way.
Of course this playing around is maybe a substitute for actual writing, but it still feels like (some sort of) progress.