Anyone else, feel free to comment and advise Alex regarding this. I’m not that knowledgeable and may be misleading him.
I’ll try a little more, but run the risk of talking beyond what I know…
My sense is that you have split and saved the book into five separate Scrivener projects, presumably in the hope of greater responsiveness/stability within Scrivener due to the smaller project sizes.
I don’t know that there is a way to include/compile separate Scrivener projects into a single output (epub, mobi, etc.) via just the use of Scrivener. I was unable to find discussion of such via a quick search and am inclined to think the option doesn’t exist… but I have a vague memory of having seen it discussed some time ago here in the forums…
It does appear that through the use of additional free software (Calibre and/or Sigil), one can combine multiple epub files produced by Scrivener and convert/output the result as a mobi file. For information on this, fire up your favoriate search engine and search on things like “merge epub”. I don’t know how simple or complicated this might prove to be.
(A side note… One can compile all or only desired portions of a project in Scrivener (specified in the expanded Compile dialog). So, if a single massive project was resulting in lengthy/unstable compiles, one could presumably compile out portions and then combine them as discussed above.)
My naive sense is that I would keep the whole thing as a single Scrivener project… and then avoid sluggishness while editing by busting the chapters into multiple smaller subordinate documents (makes for more responsive editing and when compiled the chapters still present as a whole) and working/viewing down in the lower levels of the binder hierarchy (to avoid delays due to loading lots of documents for “scrivening” view).
That’s about all I can think to offer… other than to talk a bit more about Scrivener project file structure.
To revisit Scrivener project file structure, as it exists in the computer’s operating system’s file system (rather than how a project appears within Scrivener)…
A Scrivener project will appear in the file system as a folder with .scriv on the end of its name
(ex: ExampleScrivenerProject.scriv )
The project is that folder and everything in it, not just the project.scrivx file (see next paragraph). All the material within the project folder must be kept together and should be dealt with from within Scrivener (via opening and working on the project there) and rarely if ever at the operating system file system level (i.e. poking around in it via Windows Explorer, etc.).
Within that folder will be the Files, Settings and Snapshots sub-folders… and the project index file
(in Windows, usually named by default as project.scrivx)
which is basically a database index, in XML format, to the files comprising the project,
which reside in the ExampleScrivenerProject.scriv\Docs sub-folder.
On Macs, these file system details are hidden, via feature of the Mac OS (referred to as “packages” I believe), such that a Scrivener project presents as a single thing (at least unless one goes prowling the underlying hidden file system structure). As I recall, on Macs, the .scrivx index file may be named the same as the project
(ex: ExampleScrivenerProject.scrivx)
rather than project.scrivx and the Windows version of Scrivener can handle that.
If launching/opening a Scrivener project from the desktop/file system, rather than from inside Scrivener…
On a Mac, one does that via the single project “package” mentioned above.
On Windows, one does that via the .scrivx file inside the project’s .scriv folder.
Hope the above is of some assistance. Think I’ve now ventured beyond what I know and had best shut up. Perhaps others can chime in. Best of luck.