I have what seems to be a rather complicated situation and need some advice.
I have co-authored a book with an author living in a different country. We began by using a publisher in her country but had so many difficulties with them (re: mistakes, layout) right from the beginning that it ended up with me doing all the layout, graphic design of the cover, in fact everything that the publisher should do.
When it came to printing the book we found many mistakes made in the reviews on the back cover (words missing, others joined together) that it was decided that I would publish my books here and she would get hers printed in her country using the files that I had prepared and sent to the original printer.
I have since printed and published the book on my own (i.e. I did the printing and binding and assigned myself a name as publisher) and started selling them myself. Now she tells me that she is thinking of going back to the original publisher in her country who will assign an ISBN (I haven't done this yet with my books).
I know that this publisher uses a different paper type and very slightly different size, so will I be able to assign my own ISBN to the books I self publish or can I just use the one her publisher will use even if there are the above mentioned minimal differences?