This dissertation develops novel derivational mechanics for characterizing the syntactic component of human language -- Tree Contraction Grammar (TCG). TCG falls within a general class of derivationally-oriented minimalist approaches, constituting a version of a Multiple Spell Out (MSO-)system (Chomsky 1999, Uriagereka 1999, 2002). TCG posits a derivational WORKSPACE restricting the size of structures that can be active at a given stage of derivation. As structures are expanded, workspace limitations periodically force contractions of the span of structure visible to operations. These expansion-contraction dynamics are shown to have implications for our understanding of locality of dependencies, specifically regarding successive cyclic movement. The mechanics of TCG rely on non-standard assumptions about the direction of derivation -- structure assembly is required to work top-down. TCG draws a key idea from TAG; that is, recursive structure ought to play a direct role in delimiting the range of possible interactions between syntactic elements in phases of derivation. TAG factors complex structures into non-recursive elementary trees and recursive auxiliary trees that are combinable via TAG's two operations (substitution/adjoining). In TCG the expansion of structure in the workspace is similarly limited to containing only non-recursive stretches of structure. In the course of a derivation, encountering "repeated elements" in the expanding dominance ordering forces contractions of the workspace (understood to happen in potentially different ways depending on the properties of repeated elements). In certain circumstances, repeated elements are identified, allowing information from earlier stages of derivation to be carried over to later stages, underwriting our (novel) view of successive cyclicity. Recursive structure is retained in the global "output" structure, upon parts of which we understand the workspace to be superimposed.