Indexes can be great tools for finding specific information in books. However, as we all know, they are often maddeningly incomplete. I was constantly frustrated when I was in graduate school studying for my analysis prelim exam. Royden’s Real Analysis (our text) had a terrible index. I ended up hand writing dozens of entries into the index to compensate.

When I was doing the research for my book, I had to read a lot of books, some of them huge. I discovered that many of them were on the Google Books website. It occurred to me that I could use this online resource as an efficient and complete index.

In case you do not know, Google has digitized (and made full-text searchable) over 7 million books.

For example, I recently wanted to look up “fixed point” in Computational Homology, by Kaczynski, Mischaikow, and Mrozek. I found the book on Google Books, then searched for “fixed point”. Since Google indexes every word, this is a complete index! Here’s what I found:

I clicked through, found the pages that were relevant to me, then went to the real book to read it. (I’d rather read the book on paper. Plus, this book, like many others, has a limited preview that prevents you from reading multiple pages.)

Unfortunately, Royden’s book is not available on Google Books, so even if this technology was available in 1994, I would still have been frustrated by Royden.