diff --git a/README.md b/README.md
index 2def2d60..3fe01f34 100644
--- a/README.md
+++ b/README.md
@@ -41,7 +41,7 @@ Documentation
 
 For more information about the Scheme language implemented by Cyclone, see the [R<sup>7</sup>RS Scheme Specification](http://trac.sacrideo.us/wg/wiki). 
 
-The [features](FEATURES.md) page lists the language features currently implemented.
+The [features](docs/Features.md) page lists the language features currently implemented.
 
 The [development](docs/Development.md) page contains instructions for hacking on Cyclone.
 
diff --git a/FEATURES.md b/docs/Features.md
similarity index 86%
rename from FEATURES.md
rename to docs/Features.md
index 9596d491..7e15ed30 100644
--- a/FEATURES.md
+++ b/docs/Features.md
@@ -1,6 +1,8 @@
-TODO: list of features, table of RxRS features (??), etc
+# Features
 
-R<sup>7</sup>RS Compliance
+This page summarizes the Scheme language features implemented by Cyclone.
+
+## R<sup>7</sup>RS Compliance
 
 Section | Status | Comments
 ------- | ------ | ---------
@@ -36,3 +38,11 @@ Section | Status | Comments
 6.12 Environments and evaluation | Partial |
 6.13 Input and output | |
 6.14 System interface | |
+
+## Cyclone-specific
+
+Cyclone also supports several non-standard features:
+
+- `system`
+- `command-line-arguments`
+- what else?