diff --git a/ch10_network.adoc b/ch10_network.adoc
index a657ae3d..7c66f8bf 100644
--- a/ch10_network.adoc
+++ b/ch10_network.adoc
@@ -68,7 +68,7 @@ mining pool protocols and lightweight client-access protocols.
 
 === The Network
 
-As of this writing, the main Bitcoin network,
+As ((("Bitcoin network", "nodes", "number of")))((("nodes", "number of")))of this writing, the main Bitcoin network,
 running the Bitcoin P2P protocol, consists of about 10,000
 listening nodes running various versions of Bitcoin Core and a few
 hundred nodes running various other implementations of the Bitcoin P2P