This purpose of this book is to provide you with lots of information on pair programming. If you are already pairing, then the book will give you additional insights and techniques to make your pairing even more successful. We answer many of the questions and concerns that you may have about using the technique.

In Part One, our aim is for you to gain greater understanding about pair programming. We’ll describe the technique and will be looking at pair programming from many perspectives–from those of you who want to try and those who would rather not try, from those of you who are employees trying to convince their managers to let them try and those who are managers who are trying to convince their employees to try.

In Part Two, we deal with some operational details of pairing–such as furniture and hints and tips for daily operation. We discuss the importance of pair rotation and how that can lead to better knowledge management.

In Part Three, we explain benefits and shortcomings of many different kinds of pairs and the context in which each kind of pair works best. We offer ideas to help enhance the pairing and solutions for most problem pairings. Unfortunately, not all pairs will work, and we provide ways to recognize the potential problems before they happen.

Part Four gives two case studies of pair programming in different methodologies. The first describes pairing in Extreme Programming (XP), while the second discusses the Collaborative Software Process (CSP). In both cases, pair programming is an essential ingredient to success.

We conclude in Part Five with suggestions for future directions, and we enumerate Seven Habits of Effective Pair Programmers.

Who Should Read This Book

We’ve written this book for software development team members and their managers. When we use the term “software development team,” it goes beyond those who write production code. For example, this book is certainly appropriate for team leaders and coaches, GUI designers, architects, and QA folks. This book was also written for educators who would like to try pair programming with their students. Depending on your role, may we suggest the following process for reading this book:

• Software developers and team leaders/coaches who haven’t yet tried pair programming will find Part One very useful. All should read Chapters 1-3 very carefully. If you are trying to convince your manager to transition to pair programming, Chapter 4 will be helpful. If you would like to convince your peers to give pair programming a shot, Chapter 5 is for you. If you are currently being forced into pair programming, Chapter 6 will give you some guidance. Chapter 7 will prepare you for some potential problems you may encounter. Then you can move on to the chapters in Part Two to get into some of the more operational issues you will need to deal with in a transition to pair programming. Chapter 27, “Seven Habits of Effective Pair Programmers,” will get you started on the right track. Appendix A, “Pair Programming Tutorial,” can be used to help you transition a team or convince a team to take the pair programming plunge.
• Software developers and team leaders/coaches who are currently doing pair programming should start skimming Chapters 1-3. Much of this information will be review for you, but you may pick up some additional insight. Then you can move on to the chapters in Part Two to get into some of the more operational issues. Part Three will be particularly important in guiding you to choosing the best pair for the task at hand. Chapter 27, “Seven Habits of Effective Pair Programmers,” will be a good grand finale for you. How many of these habits do you practice? Appendix D provides information about including Test-Driven Development with pair programming.
• QA personnel might be wondering how to handle a development team that has practiced or plans to practice pair programming. Chapters 1-4 will give you a solid understanding of the technique and its benefits. Chapters 10 and 26 also discuss the possibility of pair programming as a substitute to code inspections. Appendix D discusses the composition of pair programming and a testing technique called Test-Driven Development.
• Managers should start by reading Chapters 1-4 and Chapter 7 of Part One. Then, if you are trying to convince a team to try pair programming, Chapter 6 will be helpful. It advises you to run a Pair Programming Tutorial, outlined in Appendix A, with your team. Part Two provides information about operational issues of pair programming, and Chapter 26 provides information on some directions pair programming may lead to.
• Educators should read the first four chapters of Part One to gain a good basic understanding of the technique. Chapters 8, 10, and 11 provide some tactical information about your students. Depending on the skill level and mix of your students, choose some chapters in Part Three. Chapter 26 should appeal to your academic research interests, and Chapter 27 provides good information to share with your students. Appendix C was written with educators in mind and provides some sound tactical advice for using pair programming in the classroom.
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  Acknowledgments It seems to me shallow and arrogant for any man in these times to claim he is completely self-made, that he owes all his success to his own unaided efforts. Many hands and hearts and minds generally contribute to anyone’s notable achievements.
  –Walt Disney

  Anyone who knows what a Disney fanatic Bob is will understand how appropriate it is to begin our acknowledgments with a quote from Walt Disney. Undoubtedly, this book would not have been possible without the help of the hands and hearts and minds of many of our friends, family, and respected colleagues.

  Laurie: From the bottom of my heart, I thank my family for their unconditional love and support. Thanks to my husband Danny for enduring my complaining, for being my cheerleader, and for watching the kids while I was writing. I could not have done it without you! The absolute and unqualified love of our children, Christopher, Kimberly, and Brian, has always given me great strength. Your smiling eyes help put life back in perspective. I want to thank my parents for their love and support. From childhood, they inspired me always to strive for excellence and gave me a love of learning. I thank God for giving me the ability, confidence, and perseverance to write this book. Last, I want to thank my coauthor and doctoral advisor, Bob Kessler. You have been a wonderful mentor and friend over the last five years. Thanks for writing this book with me and for your tremendous support and encouragement as my advisor.

  Laurie would also like to thank her graduate students, Prashant Baheti, Puneet Bheti, Boby George, Anuja Shukla, and Kai Yang, for their research that contributed in a few areas of the book. Thanks to Matt Senter of Senternet IT Consultants (senternet.com) for preparing the second pair programming survey as a class project and experimenting with distributed pair programming. She would also like to thank Hakan Erdogmus for working with her on the thorough economic analysis of Appendix B and to acknowledge her distributed pair programming research partner, Dr. David Stotts at the University of North Carolina, Chapel Hill. Last, she would like to thank Kent Beck, Alistair Cockburn, and Jim Coplien for their support and encouragement in the early days of the pair programming research.

  Laurie would also like to mention that the research related to pair programming in the classroom was funded by the National Science Foundation. The NSF has funded research on student pair programming at both North Carolina State University and the University of California, Santa Cruz.

  Bob: First of all, I’d like to thank my family. My wife Julie has always supported my professional efforts even though I often stay up too late working. She has juggled her job and the family and has put up with all of the deadlines. Additionally she has always been there to handle the home life when I’ve been too busy. I also thank our kids, Alex and Chelsea, for helping to enrich and fulfill our lives. I’d like to thank my parents for laying the foundation that has helped me get where I am today. I’d also like to thank Martin Griss for the years of being a great mentor, colleague, and most importantly, a friend. Last, I would be remiss without thanking my coauthor Laurie. It has been a real treat to watch her grow from a brand new graduate student into a highly regarded, professional colleague. It has been a real treat for me to “pair-write” this book with her.

  Much of the writing of this book was accomplished while Bob was on sabbatical. Thus, he wants to thank the University of Utah for supporting his sabbatical, plus Hewlett-Packard and Microsoft for providing funding during his sabbatical year.

  We would both like to thank our editor, Peter Gordon. We appreciate your unfaltering guidance for making this book as marketable as possible. We’d also like to thank Jacquelyn Doucette, our production editor.

  We would also like to thank the many pair programmers who graciously allowed us to reference or quote them in this book: Ken Auer, Fred Brooks, Paul Chisholm, Wayne Conrad, Matthias Felleisen, Dick Gabriel, Bob Hartman, Bil Kleb, Andre McKinlay, Roy Miller, Don Wells, and Bill Wood. In Part Three, we thank all those who contributed the supporting quotes: Kent Beck, Anders Bengtsson, Erik Bennerhult, Jeff Canna, Dave Chaplin, Stu Charlton, Wayne Conrad, Matthew Cooke, Martin Griss, Steve Hayes, Eric Herman, Greg Houston, Ron Jeffries, Todd Jonker, Mike Lance, Jeff Langr, Lee Lichtenwalner, Michael Lindner, Iain Lowe, Tim Mackinnon, Peter Merel, Roy Miller, AK Molteni, Jim Murphy, Vera Peeters, Christian Pekeler, Markus Pfister, Norman Rekitt, Jason Rogers, John Sisk, Stephanie Ward, and Christian Wege.

  Last but not, least, we’d like to thank our book reviewers. Thanks for challenging us, correcting us, advising us, complimenting us, and encouraging us: Goerge Burcham, Alistair Cockburn, Steve Hayes, Dave Hendricksen, Ron Jeffries, Tim Mackinnon, Andrew McKinlay, Jim Murphy, Mark Paulk, Leo Scott, Dave Thomas, and Don Wells.

  A very special thanks to three reviewers who did incredibly thorough, detailed reading and gave a host of great suggestions: Paul Chisholm, Bil Kleb, and Bill Wood. Last, many thanks to Jim Coplien for kicking our you-know-what. Without your challenges, support, and guidance, this would have been a very different book.

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