diff --git a/book/source/01-intro.md b/book/source/01-intro.md
index b478f7d..02bd158 100644
--- a/book/source/01-intro.md
+++ b/book/source/01-intro.md
@@ -13,7 +13,7 @@ This text is *not* intended as a guide for end-users of OpenPGP-related software
 
 ## What is OpenPGP?
 
-OpenPGP is an open standard for cryptographic operations. It is a system based on well-understood [cryptographic building blocks](cyrptography_chapter). OpenPGP supports the secure delivery of files and messages between a sender and a recipient. It also addresses identities and their verification. OpenPGP is an outgrowth of the ["Pretty Good Privacy (PGP)"](https://en.wikipedia.org/wiki/Pretty_Good_Privacy) encryption program and has many widely used and [interoperable implementations](interop_section).
+OpenPGP is an open standard for cryptographic operations. It is a system based on well-understood [cryptographic building blocks](cryptography_chapter). OpenPGP supports the secure delivery of files and messages between a sender and a recipient. It also addresses identities and their verification. OpenPGP is an outgrowth of the ["Pretty Good Privacy (PGP)"](https://en.wikipedia.org/wiki/Pretty_Good_Privacy) encryption program and has many widely used and [interoperable implementations](interop_section).
 
 With OpenPGP, you can: