Long's lengthy and productive career as a specialist in SLA affords him exceptional experience and perspective to write about the field, and his latest work does not disappoint. This volume is divided into three sections of unequal lengths: “Theory,” “Research,” and “Practice.” There is a copious list of references, and Long introduces many interesting citations and topics that are new, even to a veteran scholar like me.

Long builds his discussion of theory on a carefully constructed foundation in the philosophy of science, accepting the existence of multiple and often conflicting theories in the field, but arguing that, ultimately, scientific progress can only be achieved if these ideas are constantly tested and challenged so that more elegant and accurate observations of SLA can eventually emerge. In the two chapters that comprise the research section, the lengthiest section of his volume, Long argues forcefully for the existence of age-related constraints on language acquisition and for the efficacy of recasts in language teaching. Again, due to the author's expertise in these areas of inquiry, old and new research studies are thoroughly reviewed, analyzed, and appraised. The final practice section covers two quite disparate topics: a detailed review of task-based instruction and a trenchant defense of theories and scientific research against a variety of criticisms recently made about their relevance to SLA inquiry.

Given Long's scholarly interest and the title of his work, obviously there is much to read here that deals with models of language acquisition and their assessment, but, surprisingly, there is also a great deal here that is relevant to classroom practice. Chapter 4, “Recasts in SLA: The Story So Far,” and chapter 5, “Texts, Tasks, and the Advanced Learner,” both report on relevant research findings and introduce some practical suggestions for classroom teaching. Still, the most interesting chapter is the final one, in which Long launches a wide-ranging and polemical defense of SLA theory and research against social relativists and postmodernists. Here, in sometimes witty and sometimes acerbic prose, he critiques specific authors and articles and goes so far as to question the competence of certain journals to function as reputable gatekeepers for the profession.

Any reader familiar with the author's long-standing work in the field will not be surprised to find that he uses Krashen's now outdated monitor theory as an illustration of how SLA theories can be assessed and found wanting. Nevertheless, irrespective of the validity of Long's assessment, I think it is helpful to point out that some theories become popular either because they are promoted to be pedagogically useful, are perceived as such, or both. Indeed, this is exactly the reason why Krashen's model remains the best known of all the models promulgated by SLA specialists, even though, as Long has correctly and consistently demonstrated, it has many theoretical limitations, has not been supported by research, and has been superseded by more effective hypotheses.

For a volume as comprehensive and as well referenced as this and for an author so experienced, it is surprising to find that certain key SLA topics, such as corpus studies, expert language learners, and fossilization, are barely even mentioned. Also, for me, the most challenging problem for our field, as well as for linguistics in general, is the way in which the lay public misperceives both language acquisition and use. To compound this problem, the media tends to focus almost exclusively on these misperceptions during the few times it chooses to deal with language matters. For example, I have continually been mortified to see that SLA research that supports claims for a critical period has been misused, magnified, and metastasized to justify the introduction of English to younger and younger groups of learners around the globe. Nevertheless, it is instructive to remember that this is Long's work, not a long one, and, overall, he has covered many issues comprehensively and incisively, and he has covered them well.