Why are spouses always relegated to a last but not least disclaimer? There is no doubt in our minds that the two people most deserving of our gratitude are Xavi Sánchez Catalán, Clinton’s long-suffering husband, and Genevieve Flanders, Zach’s fiancée. They have looked after us and loved us, picked up the slack, put up with our absence and our endless moaning about how long the book was taking, and, most importantly, they are still here.

Thank you to Shay Banon for creating Elasticsearch in the first place, and to Elastic the company for supporting our work on the book. Our colleagues at Elastic deserve a big thank you as well. They have helped us pick through the innards of Elasticsearch to really understand how it works, and they have been responsible for adding improvements and fixing inconsistencies that were brought to light by writing about them.

Two colleagues in particular deserve special mention:

Thank you to O’Reilly for undertaking this project and working with us to make this book available online for free, to our editor Brian Anderson for cajoling us along gently, and to our kind and gentle reviewers Benjamin Devèze, Ivan Brusic, and Leo Lapworth. Your reassurances kept us hopeful.

Finally, we would like to thank our readers, some of whom we know only by their GitHub identities, who have taken the time to report problems, provide corrections, or suggest improvements:

Adam Canady, Adam Gray, Alexander Kahn, Alexander Reelsen, Alaattin Kahramanlar, Ambrose Ludd, Anna Beyer, Andrew Bramble, Baptiste Cabarrou, Bart Vandewoestyne, Bertrand Dechoux, Brian Wong, Brooke Babcock, Charles Mims, Chris Earle, Chris Gilmore, Christian Burgas, Colin Goodheart-Smithe, Corey Wright, Daniel Wiesmann, David Pilato, Duncan Angus Wilkie, Florian Hopf, Gavin Foo, Gilbert Chang, Grégoire Seux, Gustavo Alberola, Igal Sapir, Iskren Ivov Chernev, Itamar Syn-Hershko, Jan Forrest, Jānis Peisenieks, Japheth Thomson, Jeff Myers, Jeff Patti, Jeremy Falling, Jeremy Nguyen, J.R. Heard, Joe Fleming, Jonathan Page, Joshua Gourneau, Josh Schneier, Jun Ohtani, Keiji Yoshida, Kieren Johnstone, Kim Laplume, Kurt Hurtado, Laszlo Balogh, londocr, losar, Lucian Precup, Lukáš Vlček, Malibu Carl, Margirier Laurent, Martijn Dwars, Matt Ruzicka, Mattias Pfeiffer, Mehdy Amazigh, mhemani, Michael Bonfils, Michael Bruns, Michael Salmon, Michael Scharf , Mitar Milutinović, Mustafa K. Isik, Nathan Peck, Patrick Peschlow, Paul Schwarz, Pieter Coucke, Raphaël Flores, Robert Muir, Ruslan Zavacky, Sanglarsh Boudhh, Santiago Gaviria, Scott Wilkerson, Sebastian Kurfürst, Sergii Golubev, Serkan Kucukbay, Thierry Jossermoz, Thomas Cucchietti, Tom Christie, Ulf Reimers, Venkat Somula, Wei Zhu, Will Kahn-Greene, and Yuri Bakumenko.