Is there some way to combine duplicate series?

Or do I have to delete three of the four after making sure all the info is on the one that will remain?

I don't think so. Can you give an example?

http://www.librarything.com/series/Montalbano
http://www.librarything.com/series/+Montalbano
http://www.librarything.com/series/Commissario+Montalbano
http://www.librarything.com/series/Inspector+Montalbano+Mysteries

are all the same series.

Different languages - that is where these come from.
Until we have the whole concept cleared a bit more, we are stuck with these (and while some of the series might be renamed across languages, if someone chooses to do a Russian one, it will still stay alone -- until someone decides to make the series names translatable or something similar)...

Montalbano will be a good name for almost any Latin-based language. But not for the rest.

Here's another one:

http://www.librarything.com/series/suske+en+wiske
http://www.librarything.com/series/Suske+en+Wiske

I'll get that one. Screaming kid day here and I can't get any real work done.

edit: Done. Someone else will have to check the numbering.

Here is a three-for:

http://www.librarything.com/series/The%252BLiberator%252BChronicles

http://www.librarything.com/series/Blake%2527s%252B7%252B-%252BThe%252BLiberator...

http://www.librarything.com/series/Blake%2527s%252B7%253A%252BThe%252BLiberator%...

Ideally the second or third would be the resulting series label (tag?).

>7 bampton: I've put all the works in the third series, see https://www.librarything.com/series/Blake%2527s%252B7%253A%252BThe%252BLiberator.... Hope this helps!

That fixed it (didn't occur to me to go with that approach).