This book examines the typology of wh-expressions and indefinite NPs within the Minimalist framework. It is divided into two parts. The first part develops Chomsky's proposal that the theoretical status of D-Structure should be nullified in favor of alternation between Lexical Merger and Chain Formation up to the point of SPELL-OUT (S-Structure). The author argues that, under Economy considerations, Lexical Merger has priority over Chain Formation in building operator-variable dependencies. A cross-linguistic correlation between wh-question and quantification is further established to show that operator-variable dependencies should be parametrized relative to operator height, namely, operators merging into CP/IP in Chinese, in PP/DP in Japanese, and into D0/N0 in English.The second part extends Diesing's Mapping Hypothesis such that syntax-semantics mapping is implemented in a local and cyclic manner, where the nuclear scope of a given cycle is defined by the notion "syntactic predicate" rather then VP. The author shows that a range of subject specificity effects in various syntactic constructions fall under this dynamic version of Mapping Hypothesis. Notable are those associated with topicalization, non-restrictive relativization, secondary prediction, and small clauses. Furthermore, existential closure is understood as a last resort to eliminate unwarranted variables within a syntactic predicate, ensuring that there is only one open place per prediction. This move proves to be a natural extension of Economy considerations to Semantics.