I like to read non-fiction books in my “field” of information and social empowerment.  And, like a lot of people, I sometimes annotate books as I read them.  In doing so, I am, in effect, “tagging” portions of the book with metadata.  I’m applying my own, personally meaningful expressions to words fixed on the page.  These tags may be explicit (as with a word or phrase jotted in the margin) or more subtle (like by underlining a particularly interesting passage).  Sometimes, that’s the last I see of these markings – which is usually fine.  Other times, I’m sure I’ll want to find the tag again.

But how?  An electronic tagging system isn’t convenient on the subway where I do a lot of my reading.  So, I thought about jotting down these tags, along with their respective page numbers, on the blank pages at the back of the book.  Then, it occurred to me (duh!) that such an idea was called an index, that there already is one at the back of the book, and that it was created for the same purpose – to help me, the reader, re-locate items and concepts scattered throughout the text.  So, why not just annotate the index itself?

This is not such a radical idea, not so different from annotating the body of the book in the first place.  And maybe “everybody else” already does this. But it had never occurred to me before (nor to several others that I mentioned it to). 

I realized that, though I had overcome my childhood qualms about writing in a book, I felt hesitant to mess around with the book’s index.  Its terse order and structure, its separation from the content of the text per se, and its accepted role of providing keys into that text, all conspire to imbue the back-of-the-book index with an authority distinct from that of the author’s written words.

And, as in information professional, I’m well aware that many (though not all) back-of-the-book indexes are constructed by conscientious professional indexers, who do a great job of identifying, disambiguating and articulating concepts that the author has carefully assembled for presentation.  But index quality is beside the point.  A back-of-the-book index – no matter how good it is – necessarily reflects somebody else’s conceptual framework and priorities.  Not mine.  A good index is a tremendously valuable tool, which I deeply appreciate and use.  But it can never reflect my own, changing intellectual perspective or emotional response.  Which is why different people’s annotations of the same book are different.

And, with this modest insight, I feel liberated to “personalize” a book’s index, to merge my subjective tags with the indexer’s “objective” terms, to make an already useful access tool more personally meaningful.  And, in this flush of discovery, I’ve only just begun to identify ways to annotate a back-of-the-book index, including:

• adding new entries in their approximate alphabetical positions;
• alphabetically adding tags in “my language” and referring to their synonymous index terms;
• adding page numbers to existing entries (which the indexer had not considered significant enough to include);
• flagging existing entries, or specific page references of existing entries, that feel particularly important or interesting;
• highlighting references to other books, authors or concepts that I want to pursue independently;
• augmenting existing entries, or specific page references of existing entries, with additional info about why they feel important;
• drawing lines between two index terms and/or tags to reveal connections not expressed by the author or indexer.

Maybe this is interesting to nobody else but me.  But if you’ve annotated your books’ indexes, please share your experience.  Was it useful?  Do you have some tips?  Did you run into problems?  Have you discovered alternatives?