Are the libraries all descended from a common root or are they really a bunch of separate libraries. If they are separate then you can add the libraries together.
The command to use is File->Import->Library. If the originals are all managed then my suggested workflow would be to:
Pick one of the libraries as the starting point. If you do not have a good backup of this library create one now. Run a library repair on this library.
While it will add time to the process I also suggest you run a library repair on each of the other libraries before importing them. This step is optional but will greatly reduce the chance of getting hung up during the import process.
Now with the first library open run the command File->Import->Library selecting one of the other libraries. Then move on to the next library. I suggest that you run a library repair between imports on the library you are importing into. Again it is optional but will reduce the chances for problems. Of course you can be flexible here. If some of the libraries are small you can do a few before running the repair.
The import command will not touch the imported libraries. When you are done you will have the new combined library and all the originals so you will need to account for this disk space wise. Also you will need to decide what to do with these extra libraries. If you do decide to delete them I would wait for a while before doing so to make sure the combined library is working OK and had all your images.
regards
