Google books is great!

Mark Gimein defends Google Books over at The Big Money. New technology can be misused, but in general I tend to agree with Gimein. Along with Amazon's Search Inside feature Google Books is an excellent resource to look up and cross-reference obscure facts and data. With the utilization of Google Translate you can even get a good sense of some books in languages you don't know (I generally use this to make sure I understand the legend for a table or figure).