What suggestions can you provide for organizing a list of worthwhile quotations in an Excel Spreadsheet?

I’ve never delved into an organized book of quotations. I usually just remember a worthy one that might add to a discussion, and I search the Internet to get the exact wording and make sure I am giving it proper attribution. It’s amazing how many things Hitler and Mussolini didn’t actually say.

But I know there are large tomes dedicated to famous quotations. How are they organized to help their readers find something that relates to a specific topic? Given that I’m using a spreadsheet to do my organizing, are there ways I can index and annotate my list that would be beyond the reach of the dead tree information industry?

So far, what I have is columns for:
Last Name, First Name, Quotation, Work, Context. I usually keep it sorted alphabetically by Last name, First name.

Work, of course, is the title of the book, article, movie, etc. where the quote first appeared. Context doesn’t get used often, but where a quote can mean several things, I use context to pin down its meaning in its original source.

I’m open to all suggestions for improvements. The list is getting long, and I’d really like to make it easy to find specific items.