This book is built on a foundation formed of many conversations—some joyful, some painful, and all sources of learning. Here are some of the people whose conversations with us have helped us grow and learn so far, and for whom we are very grateful:

Benjamin Mitchell, who introduced us to the work of Chris Argryis, and patiently worked with us as we learned conversational analysis and much more. Waseem Taj, Andy Parker, Jamie Mill, and Lisa Miller, who joined us in learning how to analyze conversations and to lose our fear of difficult interactions. Rich Koppel and Colin Berthoud, the founders of TIM Group, and the many employees there who worked with us (especially with Jeffrey), to experiment with growing a learning organization based on transparency and curiosity. Steve Freeman, who encouraged us to tell the story of the changes at TIM Group (this book doesn’t tell that story, but it does share the conversations behind those changes).

The participants in our CTO Mentoring Circles and the London Organisational Learning Meetup, which served as testbeds for many of the concepts herein.

Chris Argyris and Donald Schön, whose theories underpin so much of this book. Also those who developed their ideas, including Philip McArthur, Robert Putnam, and Diana McLain Smith of Action Design, and Roger Schwarz, whose Eight Behaviors helped us greatly in our early conversations.

Patrick Lencioni, whose model of hierarchical dysfunctions informed the order of our conversations. Amy Edmondson, who brought “psychological safety” to our vocabulary. Simon Sinek, who explained the value of Why. Stephen Bungay, who showed the value of briefing and back briefing. Brené Brown, who helped us to put the story we were telling ourselves into words. Dr. David Burns, who helped us understand the fractal nature of conversations—that we create our interpersonal reality.

Alistair Cockburn, Kent Beck, and others of the early Agile software development community who pioneered the radical idea that relationships matter, back when both of us were still trapped in the software factory. Mary Poppendieck, Tom Poppendieck, Eric Ries, and others who helped bring Lean thinking to the software world. Patrick Debois, John Allspaw, and Paul Hammond, who helped shatter the silo that remained at the last mile, and who ensured that DevOps was about culture and not just tools.

Geckoboard (including Paul Joyce and Leo Cassarani), Unmade Ltd., and Arachnys, each of whom kindly allowed us to include the details of their work with us.

Anna Shipman, whose insightful blog post became a case study.

Sofar Sounds, who kindly allowed us to include a story about them.

Sergiusz Bleja, who allowed us to include a case study we created with him.

The Belgian Federal Pensions Service, Thierry de Pauw, and Tom Jans, who kindly allowed us to include details from one of their projects as a case study.

Elisabeth Hendrickson, whose excitement about this material led her to introduce us to IT Revolution, and who additionally suggested we add “twitch” to our analysis repertoire.

Mark Coleman, who provided very useful advice at crucial stages and gave us the concept of “difficult emotional work.”

Eric Minick, whose perspective on how far we’ve come was very helpful.

Chris Matts and Cirilo Wortel, who shared stories and ideas while the book was taking shape.

Ian Ozsvald, who gave us invaluable advice and contacts at a very early stage.

Gojko Adžić, who shared much information and advice about his publishing and consulting experience, and whose joyful approach to testing and product management has been a pleasure to observe.

Paul Julius, whose suggestion that we create a conference led to Squirrel and Jeffrey meeting (and so much more). And the attendees of that conference, the Continuous Integration and Testing Conference (CITCON), to whom we have been promising this book for many years.

Alan Weiss and Gerald Weinberg, whose writings on publishing and promoting books were inspirational for us throughout.

Laurel Ruma and Melissa Duffield, who helped us solidify our very loose initial ideas for what became this book.

Anna Noak, whose patient feedback throughout the proposal and writing stages was vital to creating the finished product, and the many others at IT Revolution who contributed to this book in a plentitude of ways.

Listeners to our podcast, Troubleshooting Agile, who provided stories, advice, and a sounding board for many of our ideas; and Michelle Choi and Laura Stack, who make sure the podcast engine is always running.

The many people and teams who allowed us to coach them and learn from them over the last two decades.

Jerry Shurman and Joe Buhler, who taught Squirrel to take joy in intellectual endeavors.

Pat Yanez, Ron Fredrick, and Marilyn Fredrick, who gave Jeffrey the background to attempt the difficult.

Thanks to Robert Schuessler for keen eyes and a quick turnaround.

And finally, our families—Andreas, Anton, Eliana, Emeline, Leanne, Lisa, and Star—whose patience was tested, who never stopped believing in us, and whose support was invaluable.