Editorial and production staffs used to be glad to see final proofs go out the door. Then came ebooks.
Many publishers tack ebook-making onto the tail end of a project. This makes sense, since text and other content is final. But that is not — cannot — be the last time they look at their book. John Pettigrew has some tips and insights to offer.
Some of the info is outdated (Sigil is available again, but does not handle EPUB3 files, which are increasingly prevalent). But the concepts and the spirit are spot-on.