I bought this one because I knew I was using more server resources than I needed and I wanted to know what sort of things I could do to reduce unnecessary strain on the server.
After reading Web Caching, I soon learned that there was more to the topic than meets the eye. The chapter on politics of caching makes for interesting reading no matter who you are on the web; covering topics such as copyright, privacy and trust, offensive content and maintaining content integrity.
I also learned more about just how important caching is to the web, which convinced me that I really should make my web pages as cache friendly as possible. Not only does the creation of cache friendly pages speed up the delivery of content, but it can also reduce the cost of hosting individual web sites!
As you can imagine, there is a lot of discussion in the book about the communications between server and browser that many of us do not see. Most of this discussion focuses on the use of HTTP headers, but there is little discussion about using various scripting technologies to over-ride the default headers that are used by the server. Even an Appendix chapter to compliment the Perl example given would have been nice, as not everyone has access to their server's settings or knows how to use their language of choice to generate server headers.
All in all Web Caching is an interesting book to read as it certainly makes you think about the issues surrounding the subject. I can't help feeling however that this book was written mainly for the server administrators, as practical examples for those that have no direct control of the server are somewhat lacking...