@@ -13,4 +13,26 @@ Keep reading if you're planning to work on the Urbit interpreter, you're a
1313language implementation geek, or you don't really understand anything until
1414you've seen the actual structs.
1515
16−;list;
16+### [C runtime system](runtime)
17+
18+The Urbit interpreter is built on a Nock runtime system written
19+in C, `u3`. This section is a relatively complete description.
20+
21+### [c3: C in Urbit](c)
22+
23+Under `u3` is the simple `c3` layer, which is just how we write C
24+in Urbit.
25+
26+### [u3: Land of nouns](nouns)
27+
28+The division between `c3` and `u3` is that you could theoretically
29+imagine using `c3` as just a generic C environment. Anything to do
30+with nouns is in `u3`.
31+
32+### [u3: API overview by prefix](api)
33+
34+A walkthrough of each of the `u3` modules.
35+
36+### [How to write a jet](jetting)
37+
38+A jetting guide by for new Urbit developers.