diff --git a/vars/default_vars.yml b/vars/default_vars.yml
index ba13fdb15..38f9dde6f 100644
--- a/vars/default_vars.yml
+++ b/vars/default_vars.yml
@@ -411,7 +411,10 @@ calibre_port: 8080
 # Change calibre to XYZ add your own mnemonic URL like: http://box/XYZ
 calibre_web_path: calibre  #NEEDS WORK: https://github.com/iiab/iiab/issues/529
 
-# Calibre-Web alternative to Calibre, offers a clean/modern UX
+# WARNING: Calibre-Web (below) depends on Calibre's own /usr/bin/ebook-convert
+# program, so we recommend you install Calibre (above) too!
+
+# Calibre-Web alternative to Calibre, offers a clean/modern UX.
 calibreweb_install: True
 calibreweb_enabled: True
 calibreweb_port: 8083