Libre can print-as-brochure, but the setting is hidden on the printer settings dialog and doesn’t seem to be available in the print dialog box, at least it wasn’t for printing to PDF. I printed a large file to PDF that way, and the PDF correctly displayed A3 sheets with the real pages left and right, double sided, with pages correctly sorted, so if you’d fold in the middle, you’d get a book. The only problem is of course that if you have a book with 300 pages, you don’t want to fold 150 sheets, that way it’d become unmanageable.
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You can solve that by printing in batches, of course, like 30 pages at a time. More work, but with a better result. If you want to fold more than once, like printing 8 pages to a sheet, you will need to print multiples of 4 pages at a time, of course.
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A quote from a message that I got from RoryOF from the OpenOffice community forum (he isn’t registered here but saw this discussion):
I would use print brochure in Open/Libre-Office to print 24/28 or 32 page groupings of such a document, then fold each grouping into a binding signature and sew and bind them. Alternately, (my preference) I make a pdf file and then, using a version of Adobe Reader that runs on linux, I use “Print booklet” from it, again selecting 24/28/32 page groupings for binding.
If the entire book is printed as brochure, all 300 pages of it, then the paper stack can be guillotined (i.e. cut with professional paper cutter) down the middle, the two stacks superimposed, then the cut edge “perfect bound” (i.e, using flexible glue), like most paperbacks.
Personally I prefer to use the signatures and sew the book together, but my hobby is bookbinding
He knows what he’s talking about, so there probably is no easier way. Remember that LO Writer is a word processor, not publishing software.