diff --git a/book.toml b/book.toml
index cc9aba2d..123a57b3 100644
--- a/book.toml
+++ b/book.toml
@@ -13,6 +13,7 @@ edit-url-template = "https://github.com/crytic/building-secure-contracts/edit/ma
 cname = "crytic.github.io/building-secure-contracts"
 no-section-label = true
 additional-css = ["static/custom.css"]
+additional-js = ["static/script.js"]
 default-theme = "light"
 
 [output.html.fold]
diff --git a/static/script.js b/static/script.js
new file mode 100644
index 00000000..603e0e5a
--- /dev/null
+++ b/static/script.js
@@ -0,0 +1 @@
+<script type="text/javascript" id="hs-script-loader" async defer src="//js.hs-scripts.com/22554992.js"></script>