The studies in this collection address a topic that has recently become the focus of considerable interest in second language acquisition (SLA) research: the acquisition of articles. Languages appear to vary in whether they have articles (English, German, Norwegian do, but Chinese, Japanese, Russian do not). Languages that have articles also appear to divide into those that realise definiteness (e.g. English) and those that realise specificity (e.g. Samoan). When speakers of one type of language learn an L2 of a different type, issues of central concern to SLA research arise: the nature of L1 influence, the time course of development, ultimate attainment, the relationship between performance and competence, and the role of Universal Grammar. These issues are considered in nine studies, written by researchers whose work is at the forefront of enquiry, that offer new data, new perspectives and new insights into the way L2 speakers acquire articles.