This clear introduction offers an insight into how agreement works, and how linguists have tried to account for it. Comparing examples from a range of languages, with radically different agreement systems, it demonstrates agreement at work in a variety of constructions. It shows how agreement is influenced by the conflicting effects of sentence structure and meaning, and highlights the oddities of agreement in English. The first textbook devoted to the cross-linguistic study of the topic, Agreement will be essential reading for all those studying the structure and mechanisms of natural languages.