# Preface
## Technical storytelling
A few years ago, when I wanted to explain why I believed that distributed revision
control was important, the field was then so new that there was almost no
published literature to refer people to.
Although at that time I spent some time working on the internals of Mercurial
itself, I switched to writing this book because that seemed like the most
effective way to help the software to reach a wide audience, along with the idea
that revision control ought to be distributed in nature. I publish this book
online under a liberal license for the same reason: to get the word out.
There's a familiar rhythm to a good software book that closely resembles telling a
story: What is this thing? Why does it matter? How will it help me? How do I use
it? In this book, I try to answer those questions for distributed revision control
in general, and for Mercurial in particular.
## Thank you for supporting Mercurial
By purchasing a copy of this book, you are supporting the continued development
and freedom of Mercurial in particular, and of open source and free software in
general. O'Reilly Media and I are donating my royalties on the sales of this book
to the Software Freedom Conservancy () which
provides clerical and legal support to Mercurial and a number of other prominent
and worthy open source software projects.
## Acknowledgments
This book would not exist were it not for the efforts of Matt Mackall, the author
and project lead of Mercurial. He is ably assisted by hundreds of volunteer
contributors across the world.
My children, Cian and Ruairi, always stood ready to help me to unwind with
wonderful, madcap little-boy games. I'd also like to thank my ex-wife, Shannon,
for her support.
My colleagues and friends provided help and support in innumerable ways. This list
of people is necessarily very incomplete: Stephen Hahn, Karyn Ritter, Bonnie
Corwin, James Vasile, Matt Norwood, Eben Moglen, Bradley Kuhn, Robert Walsh,
Jeremy Fitzhardinge, and Rachel Chalmers.
I developed this book in the open, posting drafts of chapters to the book web site
as I completed them. Readers then submitted feedback using a web application that
I developed. By the time I finished writing the book, more than 100 people had
submitted comments, an amazing number considering that the comment system was live
for only about two months towards the end of the writing process.
I would particularly like to recognize the following people, who between them
contributed over a third of the total number of comments. I would like to thank
them for their care and effort in providing so much detailed feedback.
Martin Geisler, Damien Cassou, Alexey Bakhirkin, Till Plewe, Dan Himes, Paul
Sargent, Gokberk Hamurcu, Matthijs van der Vleuten, Michael Chermside, John
Mulligan, Jordi Fita, and Jon Parise.
I also want to acknowledge the help of the many people who caught errors and
provided helpful suggestions throughout the book.
Jeremy W. Sherman, Brian Mearns, Vincent Furia, Iwan Luijks, Billy Edwards,
Andreas Sliwka, Paweł Sołyga, Eric Hanchrow, Steve Nicolai, Michał Masłowski,
Kevin Fitch, Johan Holmberg, Hal Wine, Volker Simonis, Thomas P Jakobsen, Ted
Stresen-Reuter, Stephen Rasku, Raphael Das Gupta, Ned Batchelder, Lou Keeble, Li
Linxiao, Kao Cardoso Félix, Joseph Wecker, Jon Prescot, Jon Maken, John Yeary,
Jason Harris, Geoffrey Zheng, Fredrik Jonson, Ed Davies, David Zumbrunnen, David
Mercer, David Cabana, Ben Karel, Alan Franzoni, Yousry Abdallah, Whitney Young,
Vinay Sajip, Tom Towle, Tim Ottinger, Thomas Schraitle, Tero Saarni, Ted
Mielczarek, Svetoslav Agafonkin, Shaun Rowland, Rocco Rutte, Polo-Francois Poli,
Philip Jenvey, Petr Tesałék, Peter R. Annema, Paul Bonser, Olivier Scherler,
Olivier Fournier, Nick Parker, Nick Fabry, Nicholas Guarracino, Mike Driscoll,
Mike Coleman, Mietek Bák, Michael Maloney, László Nagy, Kent Johnson, Julio
Nobrega, Jord Fita, Jonathan March, Jonas Nockert, Jim Tittsler, Jeduan Cornejo
Legorreta, Jan Larres, James Murphy, Henri Wiechers, Hagen Möbius, Gábor Farkas,
Fabien Engels, Evert Rol, Evan Willms, Eduardo Felipe Castegnaro, Dennis Decker
Jensen, Deniz Dogan, David Smith, Daed Lee, Christine Slotty, Charles Merriam,
Guillaume Catto, Brian Dorsey, Bob Nystrom, Benoit Boissinot, Avi Rosenschein,
Andrew Watts, Andrew Donkin, Alexey Rodriguez, and Ahmed Chaudhary.
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