diff --git a/ch03.asciidoc b/ch03.asciidoc
index c0374cc..00a258c 100644
--- a/ch03.asciidoc
+++ b/ch03.asciidoc
@@ -573,7 +573,7 @@ In this context, the Bitcoin blockchain acts as a court system; recording the in
 
 ==== Offline vs Online, Asynchronous vs Synchronous
 
-Whens a Bitcoin user sends funds to a destination address he does not need to know anything about the recipient.
+When a Bitcoin user sends funds to a destination address he does not need to know anything about the recipient.
 The recipient could be logically speaking "online" (e.g. run a node) or could be "offline" (e.g. does not run a node, does not use any wallet currently). 
 The transaction is registered in the blockchain, and at any later point in time the recipient can have a look at it and see that has has received funds in the past. 
 In Bitcoin, the recipient can be "offline" and the interaction is asynchronous, sender and receiver do not need to synchronize in any way.