This book has an entire chapter on mass collaboration, but this book is itself a mass collaboration. Quite simply this book would not exist were it not for the generous support of many wonderful people and organizations. For that, I am extremely grateful.

Many people provided feedback about one or more of these chapters or had extended conversations with me about the book. I am grateful to Solon Baracas, Tom Boellstorff, Clark Bernier, Michael Bernstein, Megan Blanchard, Josh Blumenstock, Dalton Conley, Yo-Yo Chen, Ethan Fast, Nick Feamster, Cybelle Fox, Maggie Frye, Sharad Goel, Jake Hoffman, Joanna Huey, Patrick Ishizuka, Ben Jones, Dawn Koffman, Sasha Killewald, Harrissa Lamothe, Andrés Lajous, David Lee, Amy Lerman, Meagan Levinson, Andrew Ledford, Dai Li, Karen Levy, Ian Lundberg, Xiao Ma, Andrew Mao, John Levi Martin, Judie Miller, Arvind Naranyanan, Gina Neff, Cathy O’Neil, Nicole Pangborn, Ryan Parsons, Devah Pager, Arnout van de Rijt, David Rothschild, Bill Salganik, Laura Salganik, Christian Sandvig, Mattias Smångs, Sid Suri, Brandon Stewart, Michael Szell, Sean Taylor, Florencia Torche, Rajan Vaish, Taylor Winfield, Han Zhang, and Simone Zhang. I would also like to thank the students in Sociology 503 in the Spring 2016 for reading an early version of the manuscript, and the students in my courses over the years who have helped shape many of the ideas in this book.

I had an amazing book manuscript workshop that was organized at hosted by Princeton’s Center for the Study of Democratic Politics. I would like to thank Marcus Prior and Michele Epstein for supporting the conference. And, I would like to thank all of the participants who took time from their busy lives to help me improve the book: Elizabeth Bruch, Paul DiMaggio, Filiz Garip, Meagan Levinson, Karen Levy, Mor Naaman, Sean Taylor, Markus Prior, Jess Metcalf, Brandon Stewart, Duncan Watts, and Han Zhang. It really was a wonderful day, and I hope that I’ve been able to channel some of wisdom from that room into the final manuscript.

A few other people deserve special thanks. Duncan Watts was my dissertation adviser, and it was my dissertation research that made me realize how exciting this kind of research could be; without the experience that I had in graduate school this book would not exist. Paul DiMaggio was the first person to encourage me to write this book. It all happened one afternoon while we were both waiting for the coffee machine in Wallace Hall, and I still remember that up until that time, the idea of writing a book had never crossed my mind. Sometimes while I was actually writing this book I cursed Paul for his suggestion, but now I am deeply grateful to him for convincing me that I did in fact have something to say and that people would be interested. I’d also like to thank Karen Levy for reading nearly all of the chapters in their earliest and messiest forms; she helped me see the big picture when I was stuck in the weeds. I’d like to thank Arvind Narayanan for helping me focus and refine the arguments in the book over many wonderful lunches. Brandon Stewart was always happy to chat or look at chapter, and his insights and encouragement kept me moving forward, even when I was starting to drift sideways. And, finally, I would like to thank Marissa King for helping me come up with the title to this book one sunny afternoon in New Haven.

While writing this book, I benefited from the support of three amazing institutions. First, at Princeton University, I’m grateful to my colleagues and students in the Department of Sociology for creating and maintaining a warm and supportive culture. I would also like to thank the Center for Information Technology Policy for proving me a wonderful intellectual second home where I could learn more about how computer scientists see the world. Portions of this book where written while I was on sabbatical from Princeton. First, I would like to thank Microsoft Research, New York City for being my home in 2013-14. Jennifer Chayes, David Pennock, and the entire computational social science group were wonderful hosts and colleagues. Second, I would like to thank Cornell Tech for being my home in 2015-16. Dan Huttenlocher, Mor Naaman, and everyone in the Social Technologies Lab helped make Cornell Tech the ideal environment for me to finish this book. In many ways this book is about combining ideas from data science and social science, and I think that both Microsoft Research and Cornell Tech are models of this kind of intellectual cross-pollination.

While writing this book, I had excellent research assistance from three people. I am grateful to Han Zhang, especially for his help making the graphs in this book. I am grateful to Yo-Yo Chen, especially for her help drafting the activities in this book. Finally, I am grateful to Judie Miller, especially for her help proofreading and tracking down all kind of materials from the library.

I received helpful feedback on the ideas in this book at a number of talks. I would like to thank the organizers and participants at the following events: Cornell Tech Connective Media Seminar, Princeton Center for the Study of Democratic Politics Seminar, Stanford HCI Colloquium, Berkeley Sociology Colloquium, Russell Sage Foundation Working Group on Computational Social Science, Princeton DeCamp Bioethics Seminar, Columbia Quantitative Methods in the Social Sciences Visiting Speaker Series, Princeton Center for Information Technology Policy Technology and Society Reading Group, Simons Institute for the Theory of Computing Workshop on New Directions in Computational Social Science & Data Science, Data and Society Workshop, University of Chicago, Sociology Colloquium, International Conference on Computational Social Science, Data Science Summer School at Microsoft Research, and the Society for Industrial and Applied Mathematics (SIAM) Annual Meeting.

The web version of this book was created by Luke Baker, Paul Yuen, and Alan Ritari of the Agathon Group. Working with them on this project was a pleasure, as always. One of my favorite things about our projects together is that I continue learning from our collaborations. I would especially like to thank Luke for also developing the build process for this book and helping me navigate the dark corners of git, pandoc, and make.

This book and the accompanying website were created with a number of open source projects. I would like to thank the contributors to the following projects: git, pandoc, pandoc-crossref, pandoc-citeproc, pandoc-citeproc-preamble, Hypothesis, Middleman, Bootstrap, Nokogiri, GNU Make, Vagrant, Ansible, LaTeX, and Zotero. All graphs in this book were created in R (Team 2016), and used the following packages: ggplot2 (Wickham 2009), dplyr (Wickham and Francois 2015), reshape2 (Wickham 2007), stringr (Wickham 2015), car (Fox and Weisberg 2011), cowplot (Wilke 2016), png (Urbanek 2013), grid (Team 2016), ggrepel (Slowikowski 2016), and emojifont (Yu 2016). I would also like to thank Kieran Healy for his blog post that got me started with pandoc. And, I would like to thank Arnout van de Rijt and David Rothschild for providing data used to recreate some of the graphs from their papers, and I would like to thank Josh Blumenstock for making public replication files for his paper.

At Princeton University Press, I would like to thank Eric Schwartz who believed in this project at the beginning, and Meagan Levinson who helped make it a reality. Meagan was the best editor that a writer could have; I felt like she always was there to support this project, in good times and in bad times. And, now when I find myself giving feedback to others, I do my best to channel Meagan’s constructive and careful style.

Finally, I would like to thank my friends and family. You have been supportive of this project in so many ways, often in ways that you did not even know. I would especially like to thank my parents, Laura and Bill, and my parents-in-law, Jim and Cheryl, for their never-ending support while this project went on and on and on. I would also like to thank my kids. Eli and Theo, you have asked me so many times when my book will finally be finished. Well, the answer is now. And, most importantly, I want to thank my wife Amanda. I know that this project involved a lot of ups and downs, and I will always be grateful for your never-wavering love and support.