This book represents a sustained attempt to come to grips with some very basic questions about L2 lexical acquisition and proccssing - questions largely clustered around the relationship between the L2 mental lexicon and the L1 mental lexicon. It thus diverges from a recent trend in lexically oriented publicaions towards attempting to cover a multitude of lexical topics from a very wide variety of perspectives. The substantial review of the lexical research literature which the volume provides focuses on issues such as similarities and differences between the conditions of L1 and L2 acquisition, the respective roles of form and meaning in L1 and L2 processing, and the degree of separation/integration between L1 and L2 lexical operations. New research into the L2 mental lexicon from the Trinity College Dublin Modern Languages Research Project is considered in the latter part of volume.