Importing your books: Now let's get your books into Calibre. If you've created those smart folders I suggested, you can do this by choosing Add Books > Add Books From a Single Directory and in the sheet that appears, select the appropriate smart folder from the sidebar. Click on the first book in the resulting list, hold down the Shift key, and then click on the list's last book. Then click Open. Those books will be imported into Calibre's library.
Alternatively, if you have all your ebooks jammed into the same folder or volume rather than in a smart folder, choose Add Books > Add Books From Directories, Including Sub Directories (Multiple Books Per Directory, Assumes Every Ebooks File Is A Different Book). And yes, we have a winner for the world's longest menu command. Navigate to the folder or volume that contains your ebooks and click Choose. Calibre will dig down and add all the ebooks it finds to the library.
If you have a mix of ebook types--mobi as well as epub books--all of these files will appear in the library. We can sort them out later.
Cleaning up the metadata: You can clear up a lot of your problems simply by attaching better metadata--information such as author, title, genre, and year of publication, for example--to your books. In order to do that, select all the books in your library and choose Edit Metadata > Download Metadata And Covers. Calibre will go online and try to track down the most appropriate metadata for the books in your library, including cover art. This can take a long time if you have a large library.
Once the process is complete you'll be asked if you'd like to replace your books' metadata. Click Yes.
When you do this you'll find that your library contains more information than it once did. For example, you'll probably see more entries under Publisher than before. You might also find ratings and tags. Hopefully, title and author information will be cleaned up as well. Instead of Dickens, Charles--which is sorted under C rather than D--you should see Charles Dickens. (Though this doesn't always work.)
Removing duplicates: Let's get rid of your duplicates. To do that choose Calibre > Preferences and then click Plugins in the resulting sheet. In the next sheet click Get New Plugins. In the list that appears locate Find Duplicates, select it, and click Install. Then quit and restart Calibre.
Once restarted, Calibre will display a Find Duplicates entry in the toolbar. Click on it and in the window that appears choose Fuzzy under both the Title Matching and Author Matching headings and click OK. A list of books that are duplicated will appear. Command-click any additional copies of the book (leave one unchecked so that you don't delete the original) and then click on Remove Books in the toolbar. The duplicates will disappear.
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