In addition to the excellent advice given, you might want to consider a catalog merge if you end up using Publisher. Personally I think Word is the better choice for most large documents such as books...check Word for templates or ideas on how to use that
program.
Reference: Create a catalog merge: https://support.office.com/en-us/article/Create-a-catalog-merge-42D37310-FCAD-493F-8102-7C8EF3862EB2
I would suggest you use a third party image editor to resize and optimize all the pictures before you merge them. Newer versions of Publisher tend to choke on high resolution, large picture files. At least plan on
compressing the images within Publisher.
Check with your printer to see what resolution is needed and point out to them that you will have to send in RBG as MSFT stripped CMYK support for Publisher as of Pub 2013. (note: one user has suggested a workaround for CMYK, but I have not tested it or
confirmed it works.)
I would also suggest that you break up your publication into some sort of sections or chapters in order to keep the file size down. Large files can go corrupt. Chances are your printer is going to want a PDF from you. Ask them if they can combine multiple
PDF files as that would be safer than one large one. If you need one large PDF then you can append PDF files with the freebie PrimoPDF, a PDF tool that I have used since before MSFT added PDF functionality to Office 2007.
Finally...backup often and backup you backup files. Again, larger Publisher publication can and do corrupt. Plan accordingly.
DavidF