If you develop code behind web servers using some other technology, then go read this book anyway - it might well convince you that Java servlets are a superior solution.
For anyone that doesn't know, Java servlets are a new and elegant way of writing CGI type code behind web servers and are one of SUN's many Java extension APIs. They are well supported on most web servers, though sometimes you need to pay for a 3rd party product. Apache, the most popular and free web server, has a freely available module for adding servlet support.
This book assumes you have a basic knowledge of Java programming and a little HTML know how. It starts with the basics of what Java servlets are and why you should use them. The book then follows a nice logical progression, taking you through the principal states a servlet exists in and the methods that get called for different events. There is a good coverage of processing form input and returning HTML pages to the client, not just the normal HTML, but also images and compressed files. Of particular note is an excellent explanation of the threading issues when using servlets and the issues that you need to consider. Having covered the basics the book moves on to more complex examples, such as session tracking, servlet-applet communication, HTTP header generation and internationalisation. There are also some sections on database connectivity and RMI, giving a reasonable introduction that might be handy to use in many servlets if you are not already familiar with those Java APIs. There is also a brief section on Java Server Pages, though it's little more than an overview. Given that (at the time of writing) the specification is still in draft format, that's not unreasonable.
This is a book in the best traditions of the excellent O'Reilly series. In depth technical descriptions, good use of code examples and comprehensive coverage of the issues, all clearly and carefully explained. I did notice that this edition apparently covers version 2.0 of the servlet specification and the current version is 2.1, which has a few minor changes. The coverage of Java Server pages is also rather brief. However those are very minor criticisms, which I'm sure will be picked up in a later edition, in an otherwise excellent book. If you develop Java servlets, this book should be on your bookshelf. If you develop code behind web servers using some other technology, then go read this book anyway - it might well convince you that Java servlets are a superior solution. Recommended.