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.