This monograph presents an experimental and theoretical inquiry into the role of sentential form and variation in the prosodic structure of Catalan. The empirical section examines intonational phrasing across sentence forms, including SVO structures with either nominal or sentential objects and structures involving clitic left- and right-dislocations. The results show variation in phrasing that depends on syntactic factors and non-syntactic factors such as topic-hood and prosodic binarity. The theoretical section uses Stochastic Optimality Theory to model the variation and frequency distributions associated with the observed prosodic patterns. Various syntactic and non-syntactic factors are represented by alignment constraints, which play a major role in Catalan, and by constraints that limit size and those that limit the overall amount of prosodic structure. This study represents a combined approach to prosody and syntax and is of particular relevance for theoretical and empirical linguists interested in the relationship between these domains both in Catalan and other languages.