diff --git a/README.md b/README.md
index 3095e22..6fd9e0a 100755
--- a/README.md
+++ b/README.md
@@ -494,6 +494,10 @@ The number may be prefixed with a `-` to signify that its direction is down. E.g
 #### TeoriaInterval.value()
  - The value of the interval - That is a ninth = 9, but a downwards ninth is = -9
 
+#### TeoriaInterval.toString()
+ - Returns the *simpleInterval* representation of the interval. E.g. `'P5'`,
+ `'M3'`, `'A9'`, etc.
+
 #### TeoriaInterval.base()
  - Returns the name of the simple interval (not compound)
 
diff --git a/package.json b/package.json
index 26bb222..cc6c42e 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "teoria",
-  "version": "0.3.8",
+  "version": "0.4.0",
   "description": "Music theory for JavaScript",
   "homepage": "http://saebekassebil.github.com/teoria",
   "keywords": ["music", "theory", "jazz", "classical", "chord"],