diff --git a/book/source/02-highlevel.md b/book/source/02-highlevel.md
index 23e2f10..bccb6cd 100644
--- a/book/source/02-highlevel.md
+++ b/book/source/02-highlevel.md
@@ -96,7 +96,7 @@ There is [ongoing work](https://datatracker.ietf.org/doc/draft-wussler-openpgp-p
 
 OpenPGP revolves fundamentally around the concept of cryptographic keys.
 
-In this framework, bare cryptographic keys are combined with additional metadata to form what are known as "OpenPGP certificates." These certificates are relatively complex data structures, also commonly referred to as "OpenPGP keys".
+In this framework, bare cryptographic keys are combined with additional metadata to form what are known as "OpenPGP certificates." These certificates are relatively complex data structures, also commonly referred to as "OpenPGP keys."
 
 An OpenPGP certificate is dynamic, evolving over time as components are added, expire, or are marked as invalid.