diff --git a/ch12.asciidoc b/ch12.asciidoc
index e8c31a30..aaf37e43 100644
--- a/ch12.asciidoc
+++ b/ch12.asciidoc
@@ -1251,4 +1251,24 @@ is critical. By decentralizing the basis of trust, the Bitcoin
 blockchain is a platform that will spawn many revolutionary applications
 in a wide variety of industries.
 
-//FIXME:conclusino
+----
+
+Now that you have reached the end of this book, what will you do with
+the knowledge you have gained?  Millions of people, perhaps billions,
+know the name "Bitcoin", but only a small percentage of them know as
+much about how Bitcoin works as you now do.  That knowledge is precious.
+Even more precious are the people, such as yourself, who are so
+interested in Bitcoin that you are willing to read several hundred pages
+about it.
+
+If you haven't already begun doing so, please consider contributing to
+Bitcoin in some way.  You can run a full node to validate the Bitcoin
+payments you receive, build applications that make it easier for other
+people to use Bitcoin, or help educate other people about Bitcoin and
+its potential.  You can even take the rare step of contributing to open
+source Bitcoin infrastructure software, such as Bitcoin Core, carefully
+working with a small number of incredibly smart people to build tools
+that no one will ever pay for but that billions may one day depend upon.
+
+Whatever your Bitcoin journey, we thank you for making _Mastering
+Bitcoin_ a part of it.