This book proposes a new spell-out-based approach coached within the framework of Chomsky (2000, 2001). It defines a new spell-out mechanism that can handle existing cross-linguistic variations in what is spelled-out (and defined as a p-phrase) within a more integrated approach. Based on this spell-out-based approach, a new constraint-based system is developed translating (many of) the ways syntactic structures can be defined (mapped) onto phonological form into new OT constraints. The main assumption in this book is that phase heads belong to their spell-out domains (contra Chomsky, 2001 and subsequent work) and can regulate the spell-out process by deciding both the kind of spell-out applying and the timing of spell-out relevant. Moreover, this book introduces two new assumptions. The first assumption is that some kinds of phase heads can, in the case PIC2 is in effect, result in hindering, rather than initiating, spell-out on a previous phase, and the second is that some forms of XP movement are not motivated by an EPP feature of a strong phase head mainly v* but they are rather motivated by a last resort strategy to accomplish a spell-out instruction of this strong phase head.