That's weird you can't break it down into smaller parts? I worked on a big book, about that size with several people and the major, mainstream publishing company wanted it in individual documents mapping to individual chapters.
We actually did break it up into several parts when making and editing it, but for the "official release" of the document (It's a big-ass test procedure document), they wanted it in one file. And of course there's always some changes you find after you release something.
