this book analyzes the structure of coordination from two perspectives: the symmetrical properties the construction imposes on its conjuncts, and how conjuncts interact with other categories outside coordination with respect to agreement and other grammatical phenomena. it focuses on data from spanish as this language is characterized by its rich pattern of overt agreement between the subject and the verb, between nouns and adjectives, and also between clitics and lexical dp objects and indirect objects. -it offers a simple, unified theory of coordination within current syntactic frameworks -it provides a succinct summary of the main analysis of coordination, highlighting the most important generalizations they have made -it proposes explicit analyses for long-standing problems in issues of coordination -it provides a detailed description of agreement patterns in different languages (primarily spanish), and the connection between agreement and word order -it presents a detailed account of the connection between switch-reference and coordination.