diff --git a/README.md b/README.md
new file mode 100644
index 0000000..5aa6383
--- /dev/null
+++ b/README.md
@@ -0,0 +1,12 @@
+# itty-bitty-vtty
+A vt100 emulator for the Apple IIgs
+
+vt100, modem port, 9600 baud, 8-N-1 (MAME defaults)
+
+A vt100 emulator based on The [User Guide](https://www.vt100.net/docs/vt100-ug/contents.html). Underspecified behavior is tested with MAME's vt100 emulation.
+
+Unimplemented due to hardware limitations:
+
+* alternate character sets
+* graphic rendition (except plain/reverse)
+* 132-column mode