The book provides an in-depth examination of the core concepts and general principles of web application development, using examples from specific technologies. This conceptual knowledge is critical when designing, developing and debugging complex systems, and makes it easier to learn the new application programming interfaces (APIs) that arise in the rapidly changing Internet environment. The companion web site for the book is located at www.webappbuilders.com. The text is organized into the following sections: Core Internet protocols The HTTP protocol as a foundation for web applications Discussion of markup languages such as HTML, CSS, and XML Server and browser architecture Application design case studies using JavaEE/Struts and Ruby on Rails Survey of emerging technologies The second edition of the book has been updated with enhanced coverage of: XML applications including XSLT, XSL-FO, and XPath XML-compliant HTML including XHTML and XHTML MP Web Services protocols including SOAP and REST Platform for Privacy Preferences (P3P) Security and encryption XML and RDF query languages Cloud computing, collaborative online services, and Web 2.0 and new chapters on: JavaScript, Dynamic HTML (DHTML), and AJAX Rapid application development using Ruby on Rails Search technology including Search Engine Optimization