diff --git a/dotfiles/emacs.d/README.org b/dotfiles/emacs.d/README.org
index c381ef69..e91cff1c 100644
--- a/dotfiles/emacs.d/README.org
+++ b/dotfiles/emacs.d/README.org
@@ -255,6 +255,14 @@ Ensure by default since most of the package for which I use use-package need to
 #+BEGIN_SRC emacs-lisp
 (setq use-package-always-ensure t)
 #+END_SRC
+** Set EMACS environment variable
+Emacs cask seems to depend on the EMACS environment variable being set to the
+binary path of emacs. I found the method for getting the path to the emacs
+executable [[http://emacs.stackexchange.com/questions/6010/can-emacs-detect-the-path-of-its-executable][here]].
+#+BEGIN_SRC emacs-lisp
+(setenv "EMACS"
+        (file-truename (expand-file-name invocation-name invocation-directory)))
+#+END_SRC
 * Functions
 ** Join Paths
 Works in the same way as os.path.join in python