To Combine or not to combine?

[Lisa]

When a book (typically public domain ebooks) is listed as "TitleXYZ (plus free download of TitlePDQ, etc.)" is that considered a version of TitleXYZ or both/all titles in one volume? These cases don't usually have ISBNs.

[Gerd]

As I understand it the other book is a separate download, so the books would still be "TitleXYZ"

[rivka, Former Moderator]

An ebook omnibus edition is still an omnibus edition.