Another option (or, maybe just a different way of saying what jplumey suggested) is to create a "book" with the chapters being the individual summary of you're looking for.
Basically, I made a file in Google Docs with an alphabetical summary of all of my books- Title of book then the summary for it. Then I created a table of contents in Google docs for that file.
Downloaded as .html.
Imported it into Calibre. Used Calibre to covert it into an EPUB file (LRF didn't seem to work). Selected 'forced table of contents.'
And that's it. When the reader opens it, the whole file is considered one book. But the individual summary is considered a chapter. That way you can see the name of the book in the table of contents- allowing you to jump directly to the book you want rather than having to scroll through an ever 'enlargening'
file every time you want to want to find out about a book on your reader.
Then again, if someone has found a way which didn't take them, oh, about 5 hours of trial and error. Just don't laugh too hard at my wasted day.
I have to say Sony, you disappoint me. If the whole idea is to have my library in my reader, then I can't be expected to remember every single book that's in there.