>> Is there a way to modify the page number arbitrarily? [...]
>
> This solution may need further refinement to be completely robust.
> The idea is to take the default set of pages, create new pages with
> the desired new page numbering, and transfer the contents of the
> default pages into the new pages. To illustrate, I've incremented
> by 10 from page 3 onwards.
Excellent, thanks! It shows me that my approach was indeed naïve, and
that controlling page numbers individually is actually orthogonal to
LilyPond's modus operandi (at least the default one): It would be
necessary to have manual `\pageBreak` commands everywhere, and if you
are going this route, it's not unreasonable to use a series of
`\bookpart` blocks within a `\book` instead and set the `page-number`
property in individual `\layout` blocks.
I think this issue is worth mentioning in the NR, and I will think how
to improve the documentation accordingly.
> This was inspired by a snippet by the redoubtable Jean Abou Samra.
Sigh. He is sorely missed.
Werner