diff --git a/README.md b/README.md
index 6cb42e3..c54bd75 100644
--- a/README.md
+++ b/README.md
@@ -180,6 +180,18 @@ getType('') // returns 'String'
 isType('', String) // returns true
 ```
 
+If you just want to make sure your object _inherits_ from a particular class or
+`toStringTag` value, you can use `isInstanceOf()` like this:
+
+```js
+import { isInstanceOf } from 'is-what'
+
+isInstanceOf(new XMLHttpRequest(), "EventTarget")
+// returns true
+isInstanceOf(globalThis, ReadableStream)
+// returns false
+```
+
 ## TypeScript
 
 is-what makes TypeScript know the type during if statements. This means that a check returns the type of the payload for TypeScript users.