diff --git a/import.Rmd b/import.Rmd
index 1cd2772..77c443f 100644
--- a/import.Rmd
+++ b/import.Rmd
@@ -3,7 +3,9 @@ layout: default
 title: Data import
 output: bookdown::html_chapter
 ---
-  
+
+# Data import
+
 ## Overview
 
 You can't apply any of the tools you've applied so far to your own work, unless you can get your own data into R. In this chapter, you'll learn how to import:
diff --git a/intro.Rmd b/intro.Rmd
index 798b849..6a542b7 100644
--- a/intro.Rmd
+++ b/intro.Rmd
@@ -4,6 +4,8 @@ title: Welcome
 output: bookdown::html_chapter
 ---
   
+# Welcome
+  
 ## Overview
 
 The goal of "R for Data Science" is to give you a solid foundation into using R to do data science. The goal is not to be exhaustive, but to instead focus on what we think are the critical skills for data science:
diff --git a/transform.Rmd b/transform.Rmd
index 66ef687..f0a5bc0 100644
--- a/transform.Rmd
+++ b/transform.Rmd
@@ -4,6 +4,7 @@ title: Data transformation
 output: bookdown::html_chapter
 ---
 
+# Data transformation
 
 ## Missing values