This authoritative textbook provides an overview and analysis of current second language acquisition research conducted within the generative linguistic framework. Lydia White argues that second language acquisition is constrained by principles and parameters of Universal Grammar. The book focuses on characterizing and explaining the underlying linguistic competence of second language learners in terms of these contraints. Theories as to the role of Universal Grammar and the extent of mother tongue influence are presented and discussed, with particular consideration given to the nature of the interlanguage grammar at different points in development, from the initial state to ultimate attainment. Throughout the book, hypotheses maintaining that second language grammars are constrained by universal principles are contrasted with claims that Universal Grammar is not implicated; relevant empirical research is presented from both sides of the debate. This textbook is essential reading for those studying second language acquisition from a linguistic perspective.