diff --git a/beta/src/content/apis/react/useInsertionEffect.md b/beta/src/content/apis/react/useInsertionEffect.md
index 4b486f9e..c77d507a 100644
--- a/beta/src/content/apis/react/useInsertionEffect.md
+++ b/beta/src/content/apis/react/useInsertionEffect.md
@@ -2,27 +2,144 @@
title: useInsertionEffect
---
-
-
-This section is incomplete, please see the old docs for [useInsertionEffect.](https://reactjs.org/docs/hooks-reference.html#useinsertioneffect)
+
-
+`useInsertionEffect` is aimed at CSS-in-JS library authors. Unless you are working on a CSS-in-JS library and need a place to inject the styles, you probably want [`useEffect`](/apis/react/useEffect) or [`useLayoutEffect`](/apis/react/useLayoutEffect) instead.
+
-The signateure is identical to `useEffect`, but it fires synchronously before all DOM mutations. Use this to inject styles into the DOM before reading layout in `useLayoutEffect`. Since this hook is limited in scope, this hook does not have access to refs and cannot schedule updates.
+`useInsertionEffect` is a version of [`useEffect`](/apis/react/useEffect) that fires before any DOM mutations.
```js
-useInsertionEffect(didUpdate);
+useInsertionEffect(setup, dependencies?)
```
+---
+
+## Usage {/*usage*/}
+
+### Injecting dynamic styles from CSS-in-JS libraries {/*injecting-dynamic-styles-from-css-in-js-libraries*/}
+
+Traditionally, you would style React components using plain CSS.
+
+```js
+// In your JS file:
+
+
+// In your CSS file:
+.success { color: green; }
+```
+
+Some teams prefer to author styles directly in JavaScript code instead of writing CSS files. This usually requires using a CSS-in-JS library or a tool. There are three common approaches to CSS-in-JS you might encounter:
+
+1. Static extraction to CSS files with a compiler
+2. Inline styles, e.g. `