[Kraftwerk]

I have duplicate books, three copies of some and I want to merge them.

For example, I have three copies of a book (two in .mobi and one in .epub).
I'm thinking of using 'merge into first selected book - keep others'.
I don't want to delete any of the books in case the only one I keep has errors in it.

If I merge all the books into one (say it's one of the .mobi) and discover that book has errors, how would I choose one of the other books that has been merged, either the other .mobi or .epub and send that to my device?

Just tried 'merge into first selected book - keep others' and what I thought would happen, didn't, I was still left with 3 books.

So it looks like 'merge only formats into first selected book - delete others' is what I need to use but I don't exactly know what will be happening when I have two .mobi and one .epub, what will be happening to the two .mobi when they are merged, as I would like to keep both .mobi in case of errors in any of the copies I have?