This book attempts to clarify the nature of a phenomenon known as 'case drop' in Korean, directing special attention to subject-object asymmetries. The Nominative Case particle must not drop in a subject of a clause whereas the Accusative Case particle cannot occur to an object in fragment answers unless contrasted in the context. The book explains why restrictions on case drop apply asymmetrically between subjects and objects and also between the two distinct constructions. In the process, it will be revealed that the asymmetries in these two constructions involve totally different causes, and that the explication of one of the causes will lead us to a novel view of the correlations between the surface phonetic forms and what they are meant to indicate in terms of interpretation of the nominal arguments they mark. The goal of this book is to convince the readers that what appear to be minor and peripheral empirical phenomena in fact reflect general properties involved in specific syntactic constructions, on the one hand, and the language-specific realization of possibly universal constraints imposed on the sound (or PF) aspects of linguistic expressions, on the other hand.