diff --git a/ch13_security.adoc b/ch13_security.adoc
index 53ff0926..bde8f543 100644
--- a/ch13_security.adoc
+++ b/ch13_security.adoc
@@ -271,7 +271,7 @@ stored in different locations.
 ==== Survivability
 
 One important
-security consideration that is often overlooked is availability,
+security ((("survivability (of bitcoin access)")))((("estate planning")))consideration that is often overlooked is availability,
 especially in the context of incapacity or death of the key holder.
 Bitcoin users are told to use complex passwords and keep their keys
 secure and private, not sharing them with anyone. Unfortunately, that