This book is devoted to what Block calls the Input-Interaction-Output (IIO) model of SLA. By this model, he means SLA research conducted over the last few decades by Gass, Long, Pica, Swain, and others, generally known as the “interaction hypothesis” and the “output hypothesis.” Block's chief aim is “to critically examine some of the basic notions and assumptions that underpin this model and to suggest a more interdisciplinary and socially informed approach to SLA research” (p. vii). He takes pains to point out that his criticisms are intended to be constructive, noting that his intent is to encourage IIO researchers to look beyond what he views as a psycholinguistic bias in mainstream SLA.

In the introductory chapter, Block argues that most IIO research tends to be individualistic, mechanistic, cognitive, quantitative, and narrow in orientation and asserts that SLA researchers would benefit from following the recent trend in sociolinguistics toward utilizing more interdisciplinary perspectives. In chapter 2, he provides what he refers to as an “official history” of SLA over the past 40 years and maintains that, although IIO is a powerful model that has produced ambitious, well-developed research, it could be improved through expansion. Block then considers each letter in the SLA acronym in turn, suggesting in chapter 3 that “other” or “additional” might be a more appropriate term than “second” to express the status of languages being learned and claiming that researchers should realize that many language learners are multilingual with multiple competencies and that it is not always possible to predict what kinds of learning opportunities different contexts will provide (p. 57). In chapter 4, he argues that language use involves more than carrying out tasks and transferring information and that the concept of language should be expanded to include social aspects such as face-saving and the negotiation of identity. He claims that much research in the IIO model focuses narrowly on linguistics while “systematically [marginalizing] the social side of communication” (p. 89). In chapter 5, he presents alternatives to “acquisition” as it is currently conceptualized, submitting that sociocultural or activity theory should rival current information-processing approaches and lead to a better understanding of acquisition by integrating socially sensitive concepts such as appropriation, participation, and collaboration. In the final chapter, Block examines the future of the IIO model and SLA research and repeats his call for an expanded interdisciplinary research agenda that takes into account not only cognitive and linguistic factors but also social factors and matters of culture and identity.

Block's position and arguments are likely to attract criticism from some in the field of SLA. Long and Doughty (2003), for example, argued for SLA to be viewed as cognitive science, discussing a discernible trend for

As Block notes, his book echoes many of the characteristics of an exchange in the Modern Language Journal, primarily between Firth and Wagner (1997, 1998), who argued that there was an overly narrow cognitive bias in the field of SLA, and Gass (1998) and others, who variously argued that SLA properly investigates the processes by which a second language is learned. For example, Block claims that, although information about the L1 and gender of participants is often provided in SLA reports, this information is often not utilized in the analysis. Some SLA researchers would argue that, although it may be important to know how variables such as gender and L1 are balanced across experimental groups, such issues as whether “Spanish may be listed as the L1 of a Peruvian immigrant to the US who grew up speaking Quechua and who therefore might have extremely nuanced positions towards Spanish and Quechua and, indeed English” (p. 80) may be beyond the scope of a report of a focused learning experiment. Block's argument is that the nuanced position of the speaker may impact the study. This, of course, could also be conceptualized as an empirical question. In his carefully detailed critical assessment of a recent article by Mackey, Gass, and McDonough (2000), Block argues (fairly) that considering gender and L1 could have enriched the analysis and acknowledges that “it would mean doing a different type of research where generalizations would likely be more difficult to make and more individualized case studies would be explored” (p. 84). Because many IIO articles of the kind Block critiques conclude with calls for supplementary longitudinal work and detailed case studies, perhaps that, at least, is one area where researchers might reach agreement.

In summary, I believe that Block's book is a worthwhile read even for those who will not concur with his arguments. If nothing else, his thorough description and critique of the IIO model can be viewed as an important development in the history and legitimacy of the model.