The collection of articles in Nancy Hornberger's edited book Continua of biliteracy provides a notion of historical development and a sampling of research applications for a specific conceptualization of the phenomenon of biliteracy and multiliteracy. The collection reviews 13 years of theoretical and qualitative research generated by Hornberger's (1989) initial presentation of the continua of biliteracy. The book includes three chapters by Hornberger: the original article, the revision and development of the continua of biliteracy in light of developments in literacy research through the 1990s, written with Skilton-Sylvester (Hornberger & Skilton-Sylvester 2000), and finally an extension of the themes developed in the original model through the metaphor of ecology (Hornberger 2002). These three articles function as a theoretical framework consisting of the past, present, and future directions in research generated through this conceptualization. The other chapters report on research that utilizes Hornberger's framework, covering the issues of language policy, literate identities, teacher roles, and pedagogical practice in various locations, such as the United States, Latin America, Wales, South Africa, and India. This range of issues in a variety of settings demonstrates the robustness of the theory and exemplifies for the reader some of the options of application that it offers.

Philosophically, the agenda of the continua of biliteracy project can be seen as developing from the postmodern Zeitgeist. The postmodern critique applied to issues of nationalism questions the essence of a grand narrative that provides ideological cohesiveness through the proposition of an overriding unity (Lyotard 1984). This critique, philosophical in nature, has not been ignored by researchers in the field of language. In applied linguistics, the questioning of unity is usually construed through objections to autonomous monolingual language policies imposed on a variety of hierarchically demoralized and subjugated linguistic minorities. Applied linguistics is an empirically oriented field, and its empiricism has tended to translate theoretical concerns into observable and analyzable aspects of a phenomenon. It is in this context that Hornberger's original 1989 presentation of the continua of biliteracy played a crucial role. The original paper provided an important collection and organization of the variables that function at the confrontation sites of cross-linguistic meeting. As a form of meta-analysis, the continua of biliteracy set out in a spatial three-dimensional metaphor the variables that interact in biliterate contexts, and thus summarized the variables that need to be addressed to explain the phenomenon. This is an important conceptualization because it widened the set of variables that need to be addressed and demonstrated the concept of complex interaction among variables. The continua of biliteracy functioned as a counterweight to simplistic empirical evaluations of literacy or bilingual phenomena that did not address either the complexity of interaction or the range of variables functioning within this context. Essentially, this multivariate, three-dimensional model is a conceptualization of the theoretical complexity and richness of biliteracy. In postmodern terms, when the grand narrative is questioned, factors and groupings that had been invisible under the model of national unity suddenly emerge and enter the interpretive equation.

The revision of this model in 2002 is once again a meta-analysis of research and theory that developed into a refocusing and extension of the continua of biliteracy. The major development in the revised model is its emphasis on a critical approach to biliteracy. This development reflects changes in emphasis in the field of applied linguistics that have taken on an empowerment agenda through the propagation of causes such as human linguistic rights. The underlying position is that the analysis of biliteracy through the lens of the continua of biliteracy highlights the subjugating hierarchy of some educational and national policies and practices and at the same time offers the options of seeing, for the first time, minority or marginalized linguistic practices. To a certain extent this theme is extended in the last of the Hornberger papers in this collection (Hornberger 2002). Through the metaphor of ecology, the issues of language endangerment, language evolution, and language environment are addressed. In these two revisions of the original continua of biliteracy article, the postmodern agenda is manifest through a critical pedagogy that desires to foreground the power structures that marginalize a variety of groups and linguistic practices. This agenda is followed through in several of the actual research projects presented in this volume.

Hornberger's edited book provides a serious historical overview of the development of her thought and writing in conceptualizing bi(multi)literacy. In the afterword, Brian Street poses the question: “How much does the continua framework add to what we already know on literacy, language policy and multilingualism?” (2003:342). For a theoretical conceptualization such as the continua of biliteracy, this is a serious question that addresses both the empirical manifestations of the model as a theoretical orientation and the actual model itself. Part of the answer is to be found within the studies presented in this collection. They do address the theory, but as pointed out by Street, this is to a certain extent contrived. The studies “affiliate” themselves to the model rather than grow inherently from it. This may result from the difficulties of conceptualizing interactions involving 12 variables arranged along a series of continua. The strength of the model seems to be its conceptual organization of the variables. The model has provided a unified overview of the factors that function in studying biliterate and multiliterate phenomena. But its strength as a complex network of embedded continua makes it problematic for the practical purpose of conceptualizing specific cases of interaction among variables.

From a philosophical perspective a different difficulty arises: Perhaps the idea of unifying all the variables into a single equation is in itself problematic. Certainly a postmodern sensitivity would prefer an emphasis on locality and fragmentation rather than an overriding, unified conceptualization. The phenomenon of biliteracy and the agenda of empowerment through critical analysis may benefit from micro-theories grounded in qualitative research at specific locations with particular populations. In the final analysis, this book, with its historical development of the continua of biliteracy and series of specific applications, demonstrates that this model is a work in progress that functions as a meta-analysis of research in applied linguistics. It is one option for conceptualizing the phenomenon of biliteracy that situates more specific and localized studies in a wider frame of reference. The value of this model is demonstrated in this book; the theoretical framework of the continua of biliteracy has been one of the conceptual tools that have allowed minority voices to enter the discourse of educators, language policy makers, and researchers.