diff --git a/README.md b/README.md
index 79fcd5c..507c800 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,28 @@
-mango_one
+Mango One
 =====
 
-[Open this project in 8bitworkshop](http://8bitworkshop.com/redir.html?platform=verilog&githubURL=https%3A%2F%2Fgithub.com%2Fsehugg%2Fmango_one&file=mango1.v).
+A simple 6502-based computer inspired by the Apple I, implemented in Verilog.
+
+For the 6502 CPU, we use an [open-source model](https://github.com/Arlet/verilog-6502)
+created by Arlet Ottens.
+
+The Mango One's memory map is very similar to the Apple I:
+
+Start | End      | Description
+------|----------|----------
+$0000 | $0FFF    | RAM
+$A000 | $CFFF    | Expansion ROM
+$D010 | $D013    | 6821 PIA (keyboard, terminal)
+$FF00 | $FFFF    | Monitor ROM, CPU vectors
+
+The monitor program in ROM, MangoMon, is a custom 256-byte monitor ROM with just a few commands:
+
+Command   | Function
+----------|----------------------
+`R` `aaaa`      | Dump memory at address $aaaa
+Enter           | Dump next 8 bytes
+`W` `aaaa` `bb` | Write byte $bb at address $aaaa
+`G` `aaaa`      | Jump to address $aaaa
+
+You can [open this project in 8bitworkshop](http://8bitworkshop.com/redir.html?platform=verilog&githubURL=https%3A%2F%2Fgithub.com%2Fsehugg%2Fmango_one&file=mango1.v) and try it out!
+