Will LT warn you that you are adding a duplicate book?

I am new to LibraryThing, but I think it will work well for me. I have been adding books in three ways.
1. Automatically by barcode via the LT app.
2. Searching by ISBN, for books with ISBN but no barcode, and
3. Manually for very old, antiquarian books (of which I have many!).
As I am adding books, will LT warn me if another copy of this book has already been added to My Library?
If not, is there a fast way of searching for duplicates?
Thanks you for your help.

>1 pennyholt: In theory, yes.

If there are matching ISBNs, you certainly get a warning after entering a book.

If your new book is autocombined into the same work you already have a book in, you also get a warning. If for some reason the new book does not end up in the same work, you do not get a warning. In the same way, if the books are in the same work, but shouldn't be, you still get the warning.

Have a look at https://www.librarything.com/stats/pennyholt/workdups

Most of these should not be in the same work.

>2 MarthaJeanne: Got it! Is there a quick way to combine duplicates?
Thanks for your help

If you go to one of your duplicates, the information box on the main page will give you information about the other. Open both, check the information, decide which one you want to keep. Edit that one to include any information the other copy has that you want to keep, then delete the extra copy. I find that if I add an extra copy it usually is the one I want to delete, and that needs to be done before I start editing it. Then I edit the old copy to include new information. Of course sometimes you might want to keep both copies.

I see that my list https://www.librarything.com/stats/MarthaJeanne/workdups needs to be gone though again, but most of them I really do need both copies entered.

>3 pennyholt: Your own books? You will need to delete one of them if you do not want two of them in your catalog.

If you mean duplicates which LT does not recognize as duplicates, then you can combine them via the author page or via the workbench usually.

Thanks. Problem solved. I'm finding that everything makes sense and is highly workable. It's just that I don't know where to look for things yet. I'll get it, though. Great to know that there are such good people like yourself who help so promptly and well.

Take it from me. If you stay here 15 years, there will still be things you don't know where to look for. Or don't even know you could want to look for. But we have fun on the way.

This thread makes me happy.

FYI using the mobile app and scanning ISBNs, I never get a warning I am adding a duplicate book. Very frustrating, especially as my books move from shelf to shelf and project to project, getting added to along the way!
Be great if the app did warn a duplicate was being added.