In the 12 years since Studies in Second Language Acquisition published its firstthematic collection on L2 lexical issues, “The use and acquisition of the second languagelexicon,” edited by S. Gass (1987), the centrality of lexical development in secondlanguage acquisition has received ever increasing recognition from researchers (see, for example,volumes by Arnaud & Béjoint, 1992; Coady & Huckin, 1997; Haastrup, 1991;Haastrup & Viberg, 1998; Harley, 1995, 1996; Hatch & Brown, 1995; Huckin, Haynes,& Coady, 1993; Meara, 1992; Nation, 1990; Schmitt & McCarthy, 1997; Schreuder& Weltens, 1993; Tréville, 1993; Tréville & Duquette, 1996). The1987 collection was a leading foray into new territory, following a period of relative neglect ofthe lexicon in SLA. The issues taken up by its authors were quite diverse, ranging from theorganization and components of the L2 lexicon, to aspects of acquisition such as cross-linguisticinfluence, restructuring, and rate, to L2 lexical-use issues such as retrieval and access. Since thattime, a large body of L2 research and theory has developed around these and other topics, and ithas become possible to deal comprehensively with single core issues in L2 lexical acquisitionfrom multiple perspectives. The current collection is one such attempt, offering a set of relatedpapers on the topic of incidental L2 vocabulary acquisition. Unlike the 1987 collection, whichargued for recognition of the importance of the lexicon in a field dominantly concerned with theacquisition of syntax, the authors of the present collection assume the central importance oflexical acquisition.