J. D. Applen and Rudy McDaniel, The Rhetorical Nature of XML
University of Central Florida
Applen, J. D., and Rudy McDaniel. The Rhetorical Nature of XML: Constructing Knowledge in Networked Environments. New York: Taylor & Francis, 2009. 408 pp. $40.42 (978-0-8058-6180-8)
 In The Rhetorical Nature of XML, authors J. D. Applen and Rudy McDaniel examine interdisciplinary approaches to working with the eXtensible Markup Language, or XML, through discussions and accompanying examples that readers can work with in a hands-on manner. Additionally, the authors have paired the book with a companion website that affords users extra resources relevant to many of the chapters and topics covered in the book. With this introduction of interdisciplinarity, they draw attention to the academic potential of the work, thus including in their audience scholars as well as professionals.
 XML provides practitioners with a new knowledge management solution that can improve the transfer of knowledge and enable new ways of thinking in hierarchically managed systems. The authors claim in their introduction that they mean for this book to relate seemingly different topics of inquiry with each other for the first time in one work; these topics are the eXtensible Markup Language, knowledge management, and rhetorical theory (1). They are quick to note that they do not intend to equate the subjects; rather, they mean to explain how the three can work together for mutual benefit.
 The book's subtitle, "Constructing Knowledge in Networked Environments," proves important to the premise not only of XML as a language that connects computers and users, but also of the "knowledge exchange" inherent in information management, which serves precisely as the first chapter's opening topic. The authors frequently mention the importance for professionals to question "how the social and political context affects the use of the technology they are using, ... and how this context supports their ability to use this technology in an expansive manner" (9). The study of rhetoric applies by calling attention to the relationships between creators, users, and information.
 While the authors intend for the book to provide accessibility to readers with no knowledge of XML, prior knowledge makes comprehension of the discussion vastly less demanding and aids in working with the supplemental material. Applen and McDaniel do acknowledge that some of the material is more technical when they discuss specific aspects of the included projects in spite of their intention to provide an approachable discussion (2). However, the in-depth discussions coupled with the supplemental matter create a helpful environment for learning XML even from a fundamental level. Rarely, if ever, does the subject matter seem too difficult to work through for even a novice user.
 The first chapter begins with an exploration of knowledge management and transfer systems. Knowledge management relies on both explicit and tacit knowledge and the various ways by which they are communicated, including via community sharing such as social networks and corporation intranets. The two types of knowledge, tacit and explicit, serve as the basis for the management of information: "knowledge that we take for granted" defines the former, which an individual actively acquires through experience, while representations of knowledge by various means such as writing or models comprise the latter (16). Given the different sources and implications of these two types of knowledge, tacit knowledge "has greater value than explicit knowledge" (13). It is precisely this tacit knowledge that people can gain when they begin working together with XML in a networked environment, the authors argue. This discussion of knowledge acquisition and transfer serves as a point of transition to the authors' introduction to XML itself.
 The authors' concentration on the technical details of XML informs the topics of the several chapters subsequent to the first. Besides explanations and examples, though, each chapter also seeks to relate the technical aspects of XML to background theories of rhetoric and knowledge management; for example, the authors argue that the selection and naming of tags and attributes can reflect authors' real-world experiences and interests, stemming from a discussion of rhetorical philosophy. In short, each chapter provides examples of both practical application and theoretical background. Especially interesting is the authors' argument in the fourth chapter that the visual arrangement of XML documents, established through CSS (Cascading Style Sheets) and XSL (Extensible Stylesheet Language) style transformations, deserves as much recognition as the information itself in the transfer of knowledge. As the authors state, the employment of style sheets is useful for "separating content from form" (138). That is, XML documents enact visual rhetoric through the formatting and styles that authors assign to them, showing that the aesthetics of a document share equal import with the data contained within them. In fact, Applen and McDaniel argue that CSS fulfills the original rhetorical canon of style for electronic texts since a message can be misinterpreted if "presented in a visual style that is very much in contrast with the data" (132). Thus, the consideration of visual rhetoric seems as important in digitally marked-up text as it has been in more traditional media.
 Besides the visual rhetoric, or form, of XML, the authors also examine the rhetorical potential of XML's content. XML's tags, as Applen and McDaniel argue, exemplify knowledge encapsulation as well as customization of the information that a document builder would deem most relevant (42). As an example, they provide an inventory of produce in a garden that employs the custom tags <garden>, <fruit>, <vegetable>, and <supplier> (199). Furthermore, the way that XML content is interconnected reflects humans' natural instincts to name, order, and organize information and to recognize patterns in that information (99). As they conclude their introductory chapters to XML, the authors assert that "the act of selecting, grouping, and managing XML tags during information authoring is still fundamentally a rhetorical act" (211). Recognition of this basic fact can help information-technology students as well as professionals in deciding whether and how to incorporate XML into their projects.
 While Applen and McDaniel do not explicitly present The Rhetorical Nature of XML as a textbook designed for a specific academic class, the book does contain elements that could easily serve dually as academic or professional applications. Each chapter concludes with relevant discussion questions, activities, and sample projects which serve to highlight its main points as well as provide a framework for further exploration, either as an autonomous reader or as a group in a class that might employ this book as an instructional text. The XML examples provided throughout the chapters are clear and easy to follow; further, they serve as good models to emulate for use in one's own projects, making the book an effective and helpful guide in employing XML.
 In short, while The Rhetorical Nature of XML does not offer a new theoretical perspective on XML and its implementation, it does offer useful new insights to the recent merger between information technology and the humanities. Both scholars and professionals in the fields of knowledge management, rhetorical theory, and the digital humanities stand to benefit much from the implementation of Applen's and McDaniel's work, and each field in turn offers its unique insight to the emerging networked language of XML. Thus, a solid foundation exists in this work for future research with XML and its theoretical applications.