A book I finished recently that seems to keep coming up in conversataion is
The Search by John Battelle. It not only covers Google extensively, (up to 2005) but starts where search begins and discusses the two elements of search that are so obvious to us now, but where not at its inceptio: Discovery and Recovery.
Think about it, on the web we know the amount of info is too much to categorize, so we use search to find what we're looking for, while on our own machines we recover work (usually called Find) and pull up something we have already done. These two model are converging now with Google's Web History feature. (www.google.com/history) They record every site you've been on. Privacy issues are a huge concern with this ability to track your 'click stream.' But I have to admit - it's very useful. When I want to find that page I didn't bookmark or otherwise note, this is the easiest way to go back in time and recover it.
All these implications are discussed in The Search. It gets a little heavy with the geek speak at times, but overall a great read (listen) on something that we all use everyday.