some introduction work

src/book.css

@@ -31,10 +31,14 @@ div#title h1 {
 div#title h4 {
     font-size: 24px;
     margin-top: 4em;
+    margin-bottom: 18em;
 }
 h2 {
     font-size: 24px;
 }
+h3 {
+    font-size: 18px;
+}
 div.chapter {
     page-break-inside: avoid;
     width: 690px;
@@ -53,6 +57,9 @@ div#contents {
 div#introduction {
     page-break-after: always;
 }
+div#introduction p, h2, h3 {
+    padding: 5px 5px 5px 5px;
+}
 table td {
   border: 0;
   outline: 0;

src/introduction.html

@@ -1,5 +1,30 @@
 <h2>Introduction</h2>
   
-<p>Why you should care.</p>
+<p>Go is an open-source programming language designed for
+   building simple, fast, and reliable software. It's
+   powerful to use and fun to learn.</p>
 
-<p>This is why.</p>
+<p>This book is a hands-on introduction to Go. It gives
+   you the tools you need to understand the why of Go and
+   how to write real Go programs.</p>
+
+
+<h3>Intended Audience</h3>
+
+<p>This book is intended for experienced programmers who
+   may be new to Go. If you have previous experience with
+   languages like Ruby, Python, Javascript, C#, or Java,
+   you should find this book immediately approachable even
+   if this is your first introduction to Go. Even if
+   you've worked with Go before, you may find that the
+   material covers ideas and techniques that you haven't
+   seen elsewhere.</p>
+
+
+<h3>An Example-Based Approach</h3>
+
+<p>We believe that programmers learn to program by writing
+   programs. <i>Go by Example</i> therefore teaches Go
+   exclusively via working example programs, with each
+   chapter trying to provide the programmer a new tool for
+   writing her own programs.</p>