This volume aims to carry out a comprehensive analysis of those nouns within the structure of the noun phrase which are referred to as N+N sequences (e.g. drug addiction, computer cluster). They are studied from three perspectives, namely their status as syntactic constructs, their evolution as becoming morphological items through a process of lexicalisation – whereby they gradually acquire properties of a semantic, morphological, orthographic and phonological nature –, and their use in which several variables such as speech community, mode and textual category are in operation. Additionally, this volume touches upon the problems in establishing clear-cut boundaries between morphology and syntax in order to define their status and evolution. A comprehensive corpus analysis rounds off the study.