Primarily, this book is an introduction and tutorial on a next-generation specification language for creating interactive Web-based forms. At the same time, and to its credit, the book introduces the architecture behind XForms (the author was a member of the design team). These elements together combine to provide information on both “how you do it” and “why you do it this way.” The latter greatly aids a practitioner’s understanding of the former.

The book is divided into three main sections. The first presents an overview of the XForms processing model, namely, how the elements of an application are handled as the application executes. The model is event driven; that is, the application waits for its user to take an action, and then responds to the action. XForms is a declarative language, in which the programmer specifies the events that must be handled, how they are handled, and what processing accompanies them. One would correctly infer from the name, “XForms,” that this system provides a method for presenting interactive forms to an end user and gathering data from that user. The “X” in the name tells us that the forms are based on Extensible Markup Language (XML), which is having a major impact on many aspects of Web applications.

Section 2 includes a tutorial on XForms components, how they fit into the processing model, and how they are used. Covered here are user interface controls, creating complex user interfaces, model properties, functions, and events. The user interface model separates the data that is gathered from the method by which this data is gathered, a separation that permits application logic to be independent of the host device. In practice, what this means is that the user can access and use the same form from multiple devices with very different user interfaces, such as a computer with a Web browser, a personal digital assistant, or a cell phone. The advantage for the programmer is that the application logic needs to be specified only once. At run time, event handlers provided with the device bind the application logic to the specific characteristics of the device’s user controls.

The third and final section of the book discusses several topics about how XForms can or should be used. First comes a description of how XForms can function in conjunction with Web services. Next, there is a detailed look at multi-modal access, how XForms facilitates use of multiple devices to provide forms processing. The book concludes with a set of design principles for achieving accessible interfaces, specifically those that are usable on a variety of devices.

A CD accompanying the book includes both Hypertext Markup Language (HTML) and portable document format (PDF) versions of the complete text, including all the related XML. The only mentions of the CD are in the “How to Read this Book” and “Colophon” sections. One advantage of having the book in HTML format is that the XML can be copied, and live links are available to sections with related content. This is useful to have, because the material sometimes requires backward or forward references to other topics; links are more convenient than flipping pages. However, the CD should be more prominently mentioned in the text. Furthermore, the nature of its content is not immediately clear from the label or the initial menu page. Thus, although the CD is a good idea, its presentation could be improved.

This book is well written, and the text is refreshingly free of misprints and typographical errors. The material is presented in a straightforward and comprehensible manner, and is organized to build understanding as the reader progresses through it. Numerous examples illustrate the concepts being presented. As noted in “How to read this book,” the book is “targeted primarily at Web authors wishing to use XForms in their work. It is also meant to help information technology (IT) specialists transition from using legacy Hypertext Markup Language (HTML) forms for their Web projects.” To aid in the transition, comparisons are made between XForms and the older HTML-forms-with-scripts model. The target audience should welcome this book.