The main focus of this collection is to explore the question of “representational deficits” in second language acquisition, currently a much-debated topic. The volume is intended as a tribute to Roger Hawkins, a leading scholar in generative second language acquisition, whose research has been devoted to explaining lack of native-like success in terms of representational deficits. The papers in this volume feature a range of studies, all undertaken within a generative linguistic framework, which investigate various properties of L2 grammar bearing on the question of whether or not there are representational deficits in the post-critical-period L2 learners’ grammar. The significance of such deficits, if their existence can be confirmed, is that they provide support for the claim, at least for the type of L2 learner under investigation, that there are insurmountable obstacles to ultimate attainment.