Merge branch 'develop'

preface.asciidoc

@@ -9,15 +9,7 @@ Two years later, after creating a number of small startups to explore various bi
 
 === Intended Audience
 
-This book is mostly intended for coders. If you can use a programming language, this book will teach you how cryptographic currencies work, how to use them and how to develop software that works with them. The first few chapters are also suitable as an in-depth introduction to bitcoin for non-coders - those trying to understand the inner workings of bitcoin and cryptocurrencies. The examples are illustrated in Python and on the command-line of a Unix-like operating system such as Linux. 
-
-=== Github Source Code
-
-This book is available on Github, as a repository that contains the text, images and code: 
-
-https://github.com/aantonop/bitcoinbook
-
-Fork the book code, try the code examples, or submit corrections via Github. 
+This book is mostly intended for coders. If you can use a programming language, this book will teach you how cryptographic currencies work, how to use them and how to develop software that works with them. The first few chapters are also suitable as an in-depth introduction to bitcoin for non-coders - those trying to understand the inner workings of bitcoin and crypto-currencies.
 
 === Why Are There Bugs On The Cover?
 
@@ -25,7 +17,7 @@ The Leafcutter Ant is a species that exhibits highly complex behavior in a colon
 
 While ants form a caste-based society and have a queen for producing offspring, there is no central authority or leader in an ant colony. The highly intelligent and sophisticated behavior exhibited by a multi-million member colony is an emergent property from the interaction of the individuals in a social network. 
 
-Nature demonstrates that de-centralized systems can be resilient and can produce emergent complexity and sophistication without the need for a central authority, hierarchy or complex parts.
+Nature demonstrates that de-centralized systems can be resilient and can produce emergent complexity and incredible sophistication without the need for a central authority, hierarchy or complex parts.
 
 Bitcoin is a highly sophisticated de-centralized trust network that can support a myriad of financial processes. Yet, each node in the bitcoin network follows a few simple mathematical rules. The interaction between many nodes is what leads to the emergence of the sophisticated behavior, not any inherent complexity or trust in any single node. Like an ant colony, the bitcoin network is a resilient network of simple nodes following simple rules that together can do amazing things without any central coordination.
 
@@ -52,6 +44,24 @@ This icon signifies a tip, suggestion, or general note.
 This icon indicates a warning or caution.
 ====
 
+=== Github Source Code
+
+This book is available on Github, as a repository that contains the text, images and code: 
+
+https://github.com/aantonop/bitcoinbook
+
+Fork the book code, try the code examples, or submit corrections via Github. 
+
+=== Code Examples
+
+The examples are illustrated in Python, C++ and using the command-line of a Unix-like operating system such as Linux or Mac OSX. All code snippets are available in the Github repository and can be accessed online at https://github.com/aantonop/bitcoinbook in the +code+ subdirectory of the main repository. 
+
+All the code snippets can be replicated on most operating systems with a minimal installation of compilers and interpreters for the corresponding languages. Where necessary, we provide basic installation instructions and step-by-step examples of the output of those instructions. 
+
+Some of the code snippets and code output have been re-formatted for print. In all such cases, the lines have been split by a backslash "\" character, followed by a newline character. When transcribing the examples, remove those two characters and join the lines again and you should see identical results as shown in the example. 
+
+All the code snippets use real values and calculations where possible, so that you can build from example to example and see the same results in any code you write to calculate the same values. For example, the private keys and corresponding public keys and addresses are all real. The sample transactions, blocks and blockchain references have all been introduced in the actual bitcoin blockchain and are part of the public ledger, so you can review them on any bitcoin system.
+
 === Using Code Examples
 
 This book is here to help you get your job done. In general, if example code is offered with this book, you may use it in your programs and documentation. You do not need to contact us for permission unless you’re reproducing a significant portion of the code. For example, writing a program that uses several chunks of code from this book does not require permission. Selling or distributing a CD-ROM of examples from O’Reilly books does require permission. Answering a question by citing this book and quoting example code does not require permission. Incorporating a significant amount of example code from this book into your product’s documentation does require permission.
@@ -110,15 +120,15 @@ Watch us on YouTube: link:$$http://www.youtube.com/oreillymedia$$[]
 
 This book represents the efforts and contributions of many people. I am grateful for all the help I received from friends, colleagues and even complete strangers, who joined me in this effort to write the definitive technical book on crypto-currencies and bitcoin. 
 
-The journey to becoming an author starts long before the first book, of course. I owe my love of words and books to my mother Theresa Delaney, who raised me in a house with books lining every wall, encouraged me to read books for pleasure and instilled in me a deep respect for language. My mother also bought me my first computer in 1982, despite being a self-described technophobe. My father, Menelaos Antonopoulos, a civil engineer who just published his first book at 80 years old, was the one who taught me logical and analytical thinking and a love of science and engineering. Thanks also to Jean de Vera for her early encouragement to become an author and for always believing and insisting that I had a book in me. 
+The journey to becoming an author starts long before the first book, of course. I owe my love of words and books to my mother, Theresa, who raised me in a house with books lining every wall, encouraged me to read books for pleasure and instilled in me a deep respect for language. My mother also bought me my first computer in 1982, despite being a self-described technophobe. My father, Menelaos, a civil engineer who just published his first book at 80 years old, was the one who taught me logical and analytical thinking and a love of science and engineering. Thanks also to Jean for her early encouragement to become an author and for always believing and insisting that I had a book in me. 
 
-My first language (and schooling) was Greek, so I had to take a remedial English Writing course in my first year of university. I owe thanks to Diana Kordas, my English Writing teacher, who helped me build confidence and skills that year. As a professional, I developed my technical writing skills on the topic of data centers, writing for Network World magazine. I owe thanks to John Dix and John Gallant who gave me my first writing job as a columnist at Network World and to my editor Michael Cooney and my colleague Johna Till Johnson who edited my columns and made them fit for publication. Writing 500 words a week for four years gave me enough experience to eventually consider becoming an author. 
+My first language (and schooling) was Greek, so I had to take a remedial English Writing course in my first year of university. I owe thanks to Diana Kordas, my English Writing teacher, who helped me build confidence and skills that year. Later, as a professional, I developed my technical writing skills on the topic of data centers, writing for Network World magazine. I owe thanks to John Dix and John Gallant who gave me my first writing job as a columnist at Network World and to my editor Michael Cooney and my colleague Johna Till Johnson who edited my columns and made them fit for publication. Writing 500 words a week for four years gave me enough experience to eventually consider becoming an author. 
 
 Thanks also to those who supported me when I submitted my book proposal to O'Reilly, by providing references and reviewing the proposal. Specifically, thanks to John Gallant, Gregory Ness, Richard Stiennon, Joel Snyder, Adam B. Levine, Sandra Gittlen, John Dix, Johna Till Johnson, Roger Ver and Jon Matonis. Special thanks to Richard Kagan and Tymon Mattoszko who reviewed early versions of the proposal and Matthew Owain Taylor who copy-edited the proposal.
 
 Thanks to Cricket Liu, author of O'Reilly title "DNS and BIND" who introduced me to O'Reilly. Thanks also to Michael Loukides and Allyson MacDonald at O'Reilly who worked for months to help make this book happen. Allyson was especially patient when deadlines were missed and deliverables delayed as life intervened in our planned schedule. 
 
-The first few drafts of the first few chapters were the hardest, because bitcoin is a difficult subject to unravel. Every time I pulled on one thread of the bitcoin technology, I had to pull in the whole thing. I repeatedly got stuck and a bit despondent as I struggled to make the topic easy to understand and create a narrative around such a dense technical subject. Eventually, I decided to tell the story of bitcoin through the stories of the people using bitcoin and the whole book became a lot easier to write. I owe special thanks to Richard Kagan and Pamela Morgan who helped me unravel the story and get past the moments of writer's block, reviewing the early drafts of the book. Thanks to the developers of the San Francisco Bitcoin Developers Meetup group and Taariq Lewis, the group's co-founder, for helping to test the early material.
+The first few drafts of the first few chapters were the hardest, because bitcoin is a difficult subject to unravel. Every time I pulled on one thread of the bitcoin technology, I had to pull in the whole thing. I repeatedly got stuck and a bit despondent as I struggled to make the topic easy to understand and create a narrative around such a dense technical subject. Eventually, I decided to tell the story of bitcoin through the stories of the people using bitcoin and the whole book became a lot easier to write. I owe thanks to my friend and mentor, Richard Kagan, who helped me unravel the story and get past the moments of writer's block, and Pamela Morgan who reviewed early drafts of each chapter and asked the hard questions to make them better. Also, thanks to the developers of the San Francisco Bitcoin Developers Meetup group and Taariq Lewis, the group's co-founder, for helping to test the early material.
 
 During the development of the book, I made early drafts available on Github and invited public comments. More than a hundred comments, suggestions, corrections and contributions were submitted in response. Those contributions are explicitly acknowledged, with my thanks, in <<github_contrib>>. Special thanks to Minh T. Nguyen who volunteered to manage the Github contributions and added many significant contributions himself. Thanks also to Andrew Naugler for infographic design.