This book is for beginners. This book introduces you to the field of agile software development with C#. There are many books on C# and as many or even greater number of books on agile, but very few books combine both software development methodologies and programming language. Agile blurs the line between the roles of analyst, designer, programmer, and tester. This book follows that principle. When you learn agile, you will learn to analyze, design, develop, and test. By the end of the book, you will be given a tiny project to work on by following the agile philosophy. It is great if you can have two or three other readers to practice it together, such as in a college setting. This book is not a reference book so we can keep the materials at minimum. This book is not an in depth cover of any topic because in depth materials make it difficult for beginners. Also readers can always search the Web for details. This book requires you to type all the codes. We don't provide sample code downloads. Throughout the book, you will be given plenty of exercises in the form of Programming Challenges and Test Your Understanding. You are strongly encouraged to do all exercises while you read this book.