The articles collected in this book are concerned with the issues of restrictiveness and learnability within generative grammar, specifically, within Chomsky's 'Extended Standard Theory'. These issues have been central to syntactic research for decades and they are even more central now as results on syntactic theory, on learnability, and on acquisition begin to converge. I hope that this book can provide researchers in all of these areas with some insight into the evolution of ideas about these issues. The articles appear in their original form, with the following exceptions: A few...