Edith A. Moravcsik 
Introduction to Syntactic Theory [PDF ebook] 

This textbook provides a comprehensive, balanced introduction to syntactic theory. The author shows how the diversity of syntactic theories, which at first seems confusing, can be approached by examining how each deals with conflicting data. This approach helps the student to understand how syntactic theories are related to each other, what they necessarily have in common, and in what ways they actually differ. Theories introduced here include Transformational Generative Grammar, Relational Grammar, Word Grammar, Functional Grammar, and Optimality Theory, amongst others. An Introduction to Syntactic Theory will be essential reading for undergraduate students of linguistics, whether they are new to the subject or studying it at a more advanced level.