You should read this book if you want to:
Create XForms files in a text or XML editor
Convert existing forms (electronic or paper) to XForms
Collect XML data from users in a user-friendly way
Reduce the amount of JavaScript needed within browser interfaces
Increase the security and reliability of your current information system by combining client-side and server-side checks into a common code base
Understand how to create interactive web sites using the latest standard technology