Merge branch 'master' into develop

appendix_license_notices.asciidoc

@@ -1,7 +1,17 @@
 [appendix]
-== License Notices
+[[sources_licenses]]
+== Sources and License Notices
+
+This appendix contains attribution and license notices for material included by permission granted via open licenses.
+
+=== Sources
+
+Material was sourced from various public and open-licensed sources:
+
+* https://wiki.ion.radar.tech[ION LN Wiki]
+* https://medium.com/suredbits/lightning-101-what-is-a-lightning-invoice-d527db1a77e6["Lightning 101: What Is a Lightning Invoice?" by Suredbits]
+* https://github.com/lightningnetwork/lightning-rfc/[LN Specifications GitHub]; Creative Commons Attribution (CC-BY 4.0)
 
-This appendix contains license notices for material included by permission granted via open licenses.
 
 === BTCPay Server
 
@@ -34,7 +44,6 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 ++++
 
-
 === Lamassu Industries AG
 
 Images of the _Gaia_ Bitcoin ATM (https://lamassu.is/product/gaia) seen in <<bitcoin-atm>> are used with permission of Lamassu Industries AG. The use of these images is not an endorsement of the product or company, but are provided as a visual example of a Bitcoin ATM.

preface.asciidoc

@@ -2,7 +2,15 @@
 [[preface]]
 == Preface
 
-This book is a collaboration between Andreas M. Antonopoulos, Olaoluwa Osuntokun, and René Pickhardt.
+The Lightning Network (LN) is a second-layer peer-to-peer network that allows us to make Bitcoin payments "off-chain", meaning without committing them as transactions to the Bitcoin blockchain.
+
+LN gives us Bitcoin payments that are secure, cheap, fast, and much more private, even for  very small payments.
+
+Building on the idea of payment channels, first proposed by Bitcoin's inventor Satoshi Nakamoto, the Lightning Network is a routed network of payment channels where payments "hop" across a path of payment channels from the sender to the recipient.
+
+The initial idea of the Lightning Network was proposed in 2015 in the groundbreaking paper _""The Bitcoin Lightning Network: Scalable Off-Chain Instant Payments"_ by  Joseph Poon and Thaddeus Dryja. By 2017 there was a "test" Lightning Network running on the internet, as different groups build compatible implementations and coordinated to set some interoperability standards. In 2018 the Lightning Network went "live" and payments started flowing.
+
+In 2019 Andreas M. Antonopoulos, Olaoluwa Osuntokun, and René Pickhardt agreed to collaborate to write this book. It appears we have been successful!
 
 === How to Use This Book
 
@@ -171,8 +179,8 @@ Thank you all for supporting me throughout this journey.
 
 === Acknowledgments By René
 
-I want to thank the German education system through which I acquired the knowledge upon which my work builds. It is one of the greatest gifts I was given. 
-Similarly I want to thank the German public healthcare system and every person devoting their time into working within that industry. Your effort and endurance makes you my personal heros and I will never forget the help, patience and support I received when I was in need. 
+I want to thank the German education system through which I acquired the knowledge upon which my work builds. It is one of the greatest gifts I was given.
+Similarly I want to thank the German public healthcare system and every person devoting their time into working within that industry. Your effort and endurance makes you my personal heros and I will never forget the help, patience and support I received when I was in need.
 Thanks goes to all the students I was allowed to teach and who engaged into interesting discussions and questions. From you I learnt the most.
 I am also grateful to the Bitcoin and Lightning Network community who warmly welcomed me and to the enthusiasts and private persons who financially supported and continue to support my work.
 In particular I am grateful to all the open source developers (not only Bitcoin and Lightning Network) and to the people who fund them to make that technology possible.
@@ -204,9 +212,4 @@ Thank you.
 
 === Sources
 
-This book references various public and open-licensed sources:
-
-* https://wiki.ion.radar.tech[ION LN Wiki]
-* https://medium.com/suredbits/lightning-101-what-is-a-lightning-invoice-d527db1a77e6["Lightning 101: What Is a Lightning Invoice?" by Suredbits]
-* https://github.com/lightningnetwork/lightning-rfc/[LN Specifications GitHub]; Creative Commons Attribution (CC-BY 4.0)
-
+Some of the material in this book has been sourced from a variety of public-domain sources, open-licensed sources, or by permission. See <<sources_licenses>> for source, license and attribution details.