diff --git a/Manifest.txt b/Manifest.txt
index 941ad78..c4c194a 100644
--- a/Manifest.txt
+++ b/Manifest.txt
@@ -23,4 +23,4 @@ tufte-handout.cls
 sample-book.pdf
 sample-book.tex
 tufte-book.cls
-tufte-common.sty
+tufte-common.def
diff --git a/sample-book.pdf b/sample-book.pdf
index 31fe8c6..49f8e52 100644
Binary files a/sample-book.pdf and b/sample-book.pdf differ
diff --git a/sample-handout.pdf b/sample-handout.pdf
index 9c645b4..d5651cf 100644
Binary files a/sample-handout.pdf and b/sample-handout.pdf differ
diff --git a/tufte-book.cls b/tufte-book.cls
index 1e4e9bd..f76d8bc 100644
--- a/tufte-book.cls
+++ b/tufte-book.cls
@@ -9,7 +9,7 @@
 
 %%
 % Load the common style elements
-\input{tufte-common.tex}
+\input{tufte-common.def}
 
 
 %%
diff --git a/tufte-common.tex b/tufte-common.def
similarity index 100%
rename from tufte-common.tex
rename to tufte-common.def
diff --git a/tufte-handout.cls b/tufte-handout.cls
index a01fa5c..e130993 100644
--- a/tufte-handout.cls
+++ b/tufte-handout.cls
@@ -9,7 +9,7 @@
 
 %%
 % Load the common style elements
-\input{tufte-common.tex}
+\input{tufte-common.def}
 
 
 %%