diff --git a/persistent-outline.el b/persistent-outline.el
index 73c9a9b..a9dfa09 100644
--- a/persistent-outline.el
+++ b/persistent-outline.el
@@ -26,10 +26,26 @@
 
 (require 'eieio)
 
+(defgroup persistent-outline nil
+  "Customization settings for persistent-outline."
+  :group 'outlines)
+
+(defcustom persistent-outline-storage 'perso-filesystem-storage
+  "How to store outlines."
+  :group 'persistent-outline
+  :type '(radio
+          (const :tag "In separate file" perso-filesystem-storage)
+          (const :tag "In a file-local variable" perso-file-local-storage)))
+
+(defcustom persistent-outline-storage-directory
+  (concat user-emacs-directory "perso/")
+  "Directory where `perso-filesystem-storage' will save its files."
+  :group 'persistent-outline
+  :type 'directory)
+
 (defclass perso-file-local-storage () ())
 (defclass perso-filesystem-storage () ())
 
-(defvar perso-storage 'perso-filesystem-storage)
 (defvar perso-outline)
 
 (defun perso-outline-state ()
@@ -75,7 +91,7 @@
         outlines))
 
 (defun perso--get-filename (file)
-  (concat "~/.emacs.d/perso/"
+  (concat persistent-outline-storage-directory
           (subst-char-in-string
            ?/ ?! (replace-regexp-in-string "!" "!!" buffer-file-name))))
 
@@ -115,14 +131,15 @@
 (defun persistent-outline-save ()
   (interactive)
   (save-excursion
-    (perso-save-to-storage (make-instance perso-storage)
+    (perso-save-to-storage (make-instance persistent-outline-storage)
                            (perso-record-outline))))
 
 (defun persistent-outline-load ()
   (interactive)
   (save-excursion
     (perso-apply-outline
-     (perso-load-from-storage (make-instance perso-storage)))))
+     (perso-load-from-storage
+      (make-instance persistent-outline-storage)))))
 
 ;;;###autoload
 (define-minor-mode persistent-outline-mode