This volume is the first in the series Hamburg studies in multilingualism and consists of an introduction and 11 articles, based on presentations at two conferences at the Hamburg Multilingualism Research Centre in July 1999.

SSLA readers might want to note that most articles concern simultaneous bilingualism in young children (where older learners are investigated, this is noted). The contributions are based on longitudinal naturalistic production data (none deals with experimental data, one with introspection). Two recurrent themes are (a) the rates and reasons for mixing in bilingual children (e.g., Gawlitzek-Maiwald on German/English; Deuchar & Muntz on Spanish/English) and (b) syntactic development in bilinguals as compared to monolingual peers (Kupisch on French and French/German determiners; Bernardini on Italian and Italian/Swedish possessives and adjectives—compared to adult L2 Italian; Ezeizabarrena on Basque and Basque/Spanish optional infinitives; Hinzelin on Brazilian Portuguese/German finiteness and pronominal/null subjects; Herkenrath, Karakoç, & Rehbein on subordination in Turkish and Turkish/German; Möhring & Meisel on Verb-Object/Object-Verb orders in French/German bilingual children, with some comparison to L2 German [especially the ZISA project]). Also included is a rigorous study of syllable-final consonants in Spanish/German bilinguals and monolinguals (Lleó, Kuchenbrandt, Kehoe, & Trujillo), an introspective look at an author's trilingual Japanese/Brazilian Portuguese/English development (Kato), and a L1 multiple-grammar model (Roeper).

What strikes me as odd about the volume is its catchy but ill-fitting title: (In)vulnerable domains in multilingualism. Hardly any of the contributions address (in)vulnerability, but, rather, are based on conference presentations and do not seem purpose-written for this book. The term vulnerable domain has been used earlier by Platzack, Hulk, and Müller (the final author is also the editor of this volume) to make testable predictions about the relative difficulty of acquiring syntactic phenomena. It refers to a syntactic domain that interfaces with another, cognitive, module, namely (discourse)-pragmatics, for which a prime example is the C(omplementizer)-domain. Lower structural levels (Inflectional Phrase, Verbal Phrase) do not interface and are invulnerable. Platzack (2001) predicted that L1 and L2 learners, persons with specific language impairment, and aphasics will show evidence of nontargetlike syntax exclusively at Complementizer Phrase (CP). Hulk and Müller (2000, p. 228) also restricted nontargetlike syntax to the highest structural level but added another condition for bilingualism: If the child's input languages partially overlap at the surface level, crosslinguistic influence will occur in the vulnerable CP domain, with higher numbers of nontargetlike productions by bilinguals than by monolinguals. No crosslinguistic influence is predicted for levels lower than CP or for phenomena that are not at the syntax-pragmatics interface. These proposals certainly deserve investigation and the book title and its back cover will suggest to many readers that (in)vulnerable domains are indeed what this volume is about—it certainly suggested that to me. These readers might feel they have been misled.

Only one contribution (Kupisch) explicitly addresses the title topic, whereas another (Bernardini) touches on it. Kupisch extends vulnerable domain from the topmost clause level (CP) to the topmost level of nominals, the Determiner Phrase (DP). DP syntax interfacing with discourse-pragmatics should be difficult to aquire, resulting in nontargetlike determiner omissions. Empirically, however, Kupisch finds just the opposite for child French and, consequently, rejects vulnerable domains as universal or to do with interface status (p. 34). (An input-driven language-specific explanation for early emergence and targetlike use of determiners is proposed instead.)

Readers are left to ponder whether other contributions could be construed as shedding light on (in)vulnerability. Yet, I did not find any except Kupisch that put vulnerable-domain proposals to the test. In her editorial introduction, Müller attempts to weave (in)vulnerable domains into her summaries of contributions. However, here she uses vulnerable domain to refer to nontargetlike properties manifested in child or learner grammars and not necessarily to the topmost level with syntax-pragmatic interface character (pp. vii–ix). However, such loose use of the term makes vulnerable domain hard to test and falsify.

This said, the volume makes an excellent read on other topics. It includes several original research papers on childhood bilingualism that are beautifully written and might well become classics, in addition to some rather poorly organized papers. Readers will be pleased to find many contributions combining qualitative and quantitative data analyses, with easy-to-read graphs (certainly many more than a decade ago). I especially liked the sophisticated batteries of tests for language dominance in bilinguals (weaker vs. stronger language), where in older work readers had no choice but to take the researcher's word for it. The volume is generally well layed out and copyedited (except for typos in the references) and includes useful name and subject indexes.