title_body: Calibre - switching title and series column
upvoted_answer: No, there isn't a one click solution for swapping series and title. You can only swap title and author (in bulk metadata edit mode). If you want to automate this you have to write a (small) program that reads the metadata file (which is XML), does the swap for you, and feed it the offending files.
  
  Not helpful for the files you already imported but maybe useful to know for new ones, is that you can change the regular expression ( Preferences -> Adding Books) that tries to extract metadata from the filename. The default there however does not put something in the series field, so you might already have changed that.
  
  Biggest problem IMO is that Calibre uses the filename to guess the author/title etc, even if you add a file which has correct metadata available. I normally don't use Calibre's drag and drop feature, instead relying on programmatically adding files with the metadata extracted from the file internal data (for PDF/Epub etc) when available.