This book is an extensively revised version of the core part of my 1993 MIT doctoral dissertation, which seeks to provide a Minimalist theory of Case absorption and support it through empirical investigation. The central idea pursued is that impoverishment of phrase structure is responsible for Case absorption and that the right theory of Case checking should derive this property. Although the basic line of research on Case absorption and wh-agreement remains the same, this book incorporates a lot of new results. A principied theory of Case checking and Case absorption has been worked out in...