diff --git a/book/02-git-basics/sections/viewing-history.asc b/book/02-git-basics/sections/viewing-history.asc
index 440c7f250..3022606a6 100644
--- a/book/02-git-basics/sections/viewing-history.asc
+++ b/book/02-git-basics/sections/viewing-history.asc
@@ -296,7 +296,7 @@ d1a43f2 - reset --hard/read-tree --reset -u: remove unmerged new paths
 b0ad11e - pull: allow "git pull origin $something:$current_branch" into an unborn branch
 ----
 
-Of the nearly 40,000 commits in the Git source code history, this command shows the 6 that match those criteria.
+Of the nearly 40,000 commits in the Git source code history, this command shows the 6 that match those criteria. Note `format` is optional in `--pretty`.
 
 [TIP]
 .Preventing the display of merge commits