Looks like an internal
Search or filter function for Marvin's Library might be useful for those users who store lots of books in it. (Although I advise against such practice: the cloud, such as Dropbox or SugarSync, is more suitable for permanent books storage, while the iPad's precious and limited storage space makes it more appropriate for temporary storage of only those books you're currently reading. This will be particularly true after a future Marvin version will make it possible to restore all your bookmarks, hightlights and notes from a previously exported XHTML file; there will, then, really be little reason to keep all books you've read in the past permanently stored on your reading device. Well, at least until reading devices with terabytes of storage space become standard.)
Sometimes after importing a book into Marvin, it may not show the author and/or title correctly if the book's meta-tags are messed up, which may make the book difficult to locate among hundreds of other titles in Marvin's library. If Marvin says that the book already is in your Library, though, it definitely is. Have you tried minimizing your Library view, which makes it possible to locate a particular book faster? Also, let's not forget Marvin has 2 distinct "library shelves": "current books" and "books already read", so make sure to look for the book in both locations.
I've had a similar problem lately -- I wanted to upload the corrected EPUB version of a book into Marvin, but Marvin wouldn't let me, saying the book is already there. Maybe Marvin could ask the user a question similar to the one asked by operating systems during copy operations: "This book already seems to be in your Library. Do you still wish to import it?" And the 3 buttons with options to reply to such a question might be:
- Yes, import the book and overwrite the previous copy
- Yes, import the book but give it a different file-name (preserving also the previous copy)
- Cancel the import of this book