diff --git a/data/presets/README.md b/data/presets/README.md
new file mode 100644
index 000000000..4e9b07b6c
--- /dev/null
+++ b/data/presets/README.md
@@ -0,0 +1,75 @@
+## Presets
+
+iD uses a simple presets system based on [JSON](http://en.wikipedia.org/wiki/JSON)
+preset definitions and simple structure.
+
+## Individual Presets
+
+Specific presets are located under `data/presets/presets`. For convenience,
+they're stored in sub-directories like `data/presets/presets/leisure/park.json`,
+but these have no effect on their final functionality.
+
+## Preset Format
+
+A basic preset is of the form:
+
+```javascript
+{
+    "name": "park",
+    "match": {
+        // the geometry types for which this preset is valid.
+        // options are point, area, line, and vertex.
+        // vertexes are points that are parts of lines, like the nodes
+        // in a road
+        // lines are unclosed ways, and areas are closed ways
+        "geometry": [
+            "point", "area"
+        ],
+        // terms are synonyms for the preset - these are added to fuel
+        // the search functionality. searching for 'woodland' will bring
+        // up this 'park' preset
+        "terms": [
+            "esplanade",
+            "village green",
+            "woodland"
+        ],
+        // tags that automatically added to the feature when it's selected
+        "tags": {
+            "leisure": "park"
+        }
+    },
+    // the icon in iD which represents this feature
+    "icon": "park",
+    // A form. See the forms documentation for details of what's valid here.
+    // Forms are arrays of form field types
+    "form": [
+        "address"
+    ]
+}
+```
+
+## Forms
+
+Forms are, like presets, defined in JSON structures. A typical form is
+
+```js
+{
+    "key": "access",
+    "type": "combo"
+}
+```
+
+In which `type` is the form's type. Valid form types are
+
+* textarea
+* radio
+* combo
+* check
+* address
+* defaultcheck - a checkbox that can be yes, no, or null - not filled
+
+## Building
+
+Presets are built with the `build.js` script in iD's root. `build.js` combines
+all presets together with imagery data, deprecated and discarded tags into
+one file, `data/data.js`.
diff --git a/data/presets/categories.json b/data/presets/categories.json
index 2b5138900..0ac205bdb 100644
--- a/data/presets/categories.json
+++ b/data/presets/categories.json
@@ -1,5 +1,4 @@
-[
-{
+[{
     "match": {
         "geometry": "line"
     },
@@ -15,6 +14,4 @@
         "service road",
         "other"
     ]
-}
-]
-
+}]