[Rique]

@emellaich, thanks for the thoughtful and helpful reply! Naturally, your answers give birth to more questions.

I'm not sure what you mean in terms of compatibility. You need to be aware that Calibre creates its own directory structure in order to manage the books it catalogs.

Meaning, it creates its own directory structure within the desktop library? Does that have any effect on the directory structure within the Sony Reader?

It first creates folders for each author. Then within the author folder it creates a folder for each book title. When you 'add' a book to Calibre it leaves the original book where it is and then creates a new copy and places it in the proper Calibre folder hierarchy.

When you say "it leaves the original book where it is", I am assuming you mean "where it is" on the computer? It does not alter the location of the original file on the PC? Yes?

Now, there is nothing special about these folders.

Meaning, the Calibre folders?

Using Windows you can browse to the folders on your computer and see the documents with no problem.

Meaning, Calibre's folder hierarchy is not packaged in an internally managed binary - it can be accessed on the computer, making use of the standard Windows (or Mac) folder structure?

However, this means that you can't read the same physical book collection from two different library software programs.

Meaning, Calibre's library must be "read" with Calibre, separately from the Sony library or the Adobe Digital Edition's Library? Each maintains and addresses such libraries separate from the other.

Each program would catalog their own set of books. If you need to share a book, then Calibre would copy it from the original place into its directory structure. Furthermore, any changes that affect the physical file would need to occur in two places.

Meaning, that each library has its own copy of the book? Yes?

To clarify, I will not be maintaining the same books in differing libraries. I will have a set of books from Sony, a set of books from ADE, and a set of books from Calibre (acquired from Fictionwise and other sources requiring a conversion). My primary concern is the effect (or lack of same) to the Reader.

Your info is very helpful - however, I am not certain yet as to the effect of all of these different libraries to the Reader - I assume the Reader will "handle" it all?

Thanks for all of your time and trouble! -- Rique

[edited a typo - RS]