The tools of the Web provide a backdrop for many kinds of application development. In addition to simple web pages and web forms, developers are putting together complex applications that place reservations, track inventory, and process purchase orders. This hour described some of the technologies at the heart of the web service paradigm. You learned about the web service infrastructure and why it is important. This hour also discussed three important web service components: XML, SOAP, and WSDL. Lastly, this hour took a look at the structure of web-based transactions.