Keith Brown & Jim Miller 
Syntax [PDF ebook] 
A Linguistic Introduction to Sentence Structure

The second edition of this invaluable introductory text takes account of developments in syntactic studies. Dealing with the whole range of syntax, this book explains, in a lucid and approachable way, why linguists have adopted certain solutions to problems and not others. This book introduces the basic concepts used in the description of syntax, independently of any single model of grammar. Profusely illustrated with diagrams, there are sets of exercises for every chapter which can be used in class or by students working independently.