Copyright © 2014 by Andreas M Antonopoulos LLC Copyright © 2017 by Andreas M Antonopoulos LLC Copyright © 2018 by aantonop Books LLC Copyright © 2023 David Harding Different editions of this book are covered by different licenses. Contributions to this book are made under public domain (CC0) or attribution licenses (CC-BY) - see CONTRIBUTING.md "Mastering Bitcoin: Unlocking Digital Currencies" (1st Edition) by Andreas M. Antonopoulos, which is tagged "Edition1Print2" is licensed under the Creative Commons Attribution-ShareAlike 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-sa/4.0/. "Mastering Bitcoin: Programming the Open Blockchain" (2nd Edition) by Andreas M. Antonopoulos, which is tagged "second_edition_print3" is licensed under the Creative Commons Attribution-ShareAlike 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-sa/4.0/. "Mastering Bitcoin: Programming the Open Blockchain" (3rd Edition) by Andreas M. Antonopoulos & David Harding, will initially be released under a Creative Commons Non-Commercial, No-Derivative (CC-BY-NC-ND) license. After one year from the date of publication we intend to release the third edition under a Creative Commons Attribution-ShareAlike (CC-BY-SA) license. These "Free Culture" licenses were approved by the publisher O'Reilly Media (http://oreilly.com). O'Reilly Media is not just the world's best publisher of technical books but also a strong supporter of an open culture and the sharing of knowledge. Thank you O'Reilly!