I have 2 machines: one is a Mac and one is Windows. Each has a copy of the photos (identical directory structure) and its own lightroom catalog.
All the individual photos/xmp are perfectly syncronized.
If I create a book on machine A, can I copy it to machine B?
How? Export as catalog without the originals/Reimport? Does it work for books?
It's the most likely way. I'd have to try it myself to be certain, so why not try it yourself?
What I suspect will happen is that machine B will import the images and display them and their folders "missing" question marks. Youl would then fix the question marks as normal.
When you bring the catalogue onto B, consider opening the catalogue directly and cleaning it up (as above) before importing it into your main catalogue.
Sure, I would back up my catalog before importing.
I'm asking this question without trying myself because I have my laptop (which is machine A)... but I don't have machine B here
An early draft of the book is on my laptop [very early.. so early that I can delete it]: I'd like to work on it these days, and continue on the [powerful] machine B as soon as possible. But if it turns out that it's impossible/unsupported to perform the copy later, I will postpone any work.
Well, I suspect there won't be many people who have already tried it or are going to go and test it for you. I'm pretty sure it should work as I've described though. The main problems will be the Mac/PC paths and the risk of importing a book pointing to duplicate images in Mac folders, and I think you'll get round these issues by cleaning up the missing files/folders on B before importing the catalogue into your main one.
I have done it from PC (Book built) to Mac (to show as a teaching example)
I did it with Export as a catalog and then integrating the book-only catalog into an existing teaching catalog.
That said, I don't think it is a common operation.
I have done it about a hundred times in the last few weeks, before finally
finishing and uploading my book last Tuesday.
All in all, book exporting/importing works well. Even if I have manually
edited some layout template resource files on one of the machines.
At some point, a few images were missing from the pages after import. I
couldn't figure out why, and after a few more import/export sessions the
problem resolved itself.
Also, as in any other collection, Import adds, but not removes from a
collection. So, if you have removed files froma collection on one machine,
delete the book on the other before importing.