Along the lines of current research, this dissertation tackles the structure of nominal phrases. First, it identifies the different positions that determiners, adjectives, demonstratives and possessives occupy, as well as the structural nature of nominalizations. Second, it sheds light on the categorial status of the different elements that can appear with the noun in the DP, and moreover it determines the types of syntactic movement operations that mediate between the initial structure and the final word order within the DP. Moreover, a new classification of adjectives is provided. Higher adjectives are those that are always prenominal in Romance, and those that dramatically undergo a change in meaning when in prenominal position. Lower adjectives are those that are postnominal, and sometimes can be focalized raising to a prenominal position.