Some people—and I count myself among them—find that syntax has its own inherent fascination. I won't hold it against you, however, if you're not one of those people. There are still many good reasons to learn something about syntax. Writing in any sort of formal context—a college paper, a memo at work, or a newspaper article—requires some knowledge of syntax. To understand the conventional rules for sentence punctuation, for example, you must first understand clause and phrase structure. Beyond mere mechanics, a thorough understanding of syntax also gives you a way to take control of your own writing. When you understand how sentences are put together, you will be able to analyze your own writing and understand the structures that you have been using intuitively. You will also be able to see what other options are available to you, how it might otherwise be done. Those who write for a living or who help others with their written expression—teachers, editors, etc.—have an even greater need to know how to analyze syntax.
When we analyze a sentence, we take it apart to determine what function each unit in the sentence has. This process is known as parsing a sentence. You can probably do some basic parsing already, even if you have never heard of the term. For example, if you can identify the subject of a sentence, you have analyzed the sentence and identified the role of one important item in it. Congratulations, you have just parsed a sentence, although not completely.
Over the next ten chapters, we will develop a progressively more detailed account of English syntax. As we begin our study, you should be aware that syntax is an interrelated system. As a result, learning how to analyze it can be challenging because to understand one part you often need to know about something else. Occasionally we will have to introduce a term before defining it completely. In these cases, you may find it helpful to reread earlier sections after you understand the concept. We start with relatively general points and refine our account as we learn more about the various components of grammar. As our account grows more detailed, we will be able to analyze more and more complex sentences. From time to time, this added complexity will force us to refine our account when our first approximation turns out to be inadequate. Although it may seem more convenient to work from the beginning with a single "correct" system, that method is actually impractical. If we did so, we would drown in detail before understanding the basics.
The chapters that follow do contain many details, but they will not be exhaustive. No book can give a complete account of something as flexible and multifaceted as a human language. Even more important than all the terminology and diagrams that we use to describe syntactic structure are the basic principles that will let us think through problems on our own. When we turn to examine real-world language, as opposed to the deliberately controlled sentences of grammar books, we must understand the principles that underlie grammatical structure and apply our knowledge.