diff --git a/src/malli/core.cljc b/src/malli/core.cljc
index b9fe27ff5..4dc79301e 100644
--- a/src/malli/core.cljc
+++ b/src/malli/core.cljc
@@ -2950,7 +2950,9 @@
                                               :compile (fn [_ [child] _] {:pred (-safe-pred #(v % child))})})]))
        (into {}) (reduce-kv assoc nil)))
 
-(defn type-schemas []
+(defn type-schemas
+  "A map from type to Schema."
+  []
   {:any (-any-schema)
    :some (-some-schema)
    :nil (-nil-schema)
@@ -2965,7 +2967,9 @@
    :qualified-symbol (-qualified-symbol-schema)
    :uuid (-uuid-schema)})
 
-(defn sequence-schemas []
+(defn sequence-schemas
+  "A map from type to Schema."
+  []
   {:+ (-sequence-schema {:type :+, :child-bounds {:min 1, :max 1}, :keep true
                          :re-validator (fn [_ [child]] (re/+-validator child))
                          :re-explainer (fn [_ [child]] (re/+-explainer child))
@@ -3023,7 +3027,9 @@
                                   :re-transformer (fn [_ children] (apply re/alt-transformer children))
                                   :re-min-max (fn [_ children] (reduce -re-alt-min-max {:max 0} (-vmap last children)))})})
 
-(defn base-schemas []
+(defn base-schemas
+  "A map from type to Schema."
+  []
   {:and (-and-schema)
    :andn (-andn-schema)
    :or (-or-schema)
@@ -3049,10 +3055,13 @@
    :schema (-schema-schema nil)
    ::schema (-schema-schema {:raw true})})
 
-(defn default-schemas []
+(defn default-schemas
+  "A map from type to Schema."
+  []
   (merge (predicate-schemas) (class-schemas) (comparator-schemas) (type-schemas) (sequence-schemas) (base-schemas)))
 
 (def default-registry
+  "A malli.registry/Registry."
   (let [strict #?(:cljs (identical? mr/mode "strict")
                   :default (= mr/mode "strict"))
         custom #?(:cljs (identical? mr/type "custom")
diff --git a/src/malli/registry.cljc b/src/malli/registry.cljc
index 79e9fe3f3..45b3e5557 100644
--- a/src/malli/registry.cljc
+++ b/src/malli/registry.cljc
@@ -1,4 +1,7 @@
 (ns malli.registry
+  "Conventions:
+   - ?registry: may be nil, Registry, or a map.
+   - ?registries: a collection of ?registry"
   (:refer-clojure :exclude [type])
   #?(:clj (:import (java.util HashMap Map))))
 
@@ -14,20 +17,26 @@
 
 (defn registry? [x] (#?(:clj instance?, :cljs implements?) malli.registry.Registry x))
 
-(defn fast-registry [m]
+(defn fast-registry
+  "Create a Registry from a map."
+  [m]
   (let [fm #?(:clj (doto (HashMap. 1024 0.25) (.putAll ^Map m)), :cljs m)]
     (reify
       Registry
       (-schema [_ type] (.get fm type))
       (-schemas [_] m))))
 
-(defn simple-registry [m]
+(defn simple-registry
+  "Create a Registry from a map."
+  [m]
   (reify
     Registry
     (-schema [_ type] (m type))
     (-schemas [_] m)))
 
-(defn registry [?registry]
+(defn registry
+  "Converts input to a Registry or nil"
+  [?registry]
   (cond (nil? ?registry) nil
         (registry? ?registry) ?registry
         (map? ?registry) (simple-registry ?registry)
@@ -39,7 +48,9 @@
 
 (def ^:private registry* (atom (simple-registry {})))
 
-(defn set-default-registry! [?registry]
+(defn set-default-registry!
+  "Set the default registry"
+  [?registry]
   (if-not #?(:cljs (identical? mode "strict")
              :default (= mode "strict"))
     (reset! registry* (registry ?registry))
@@ -51,20 +62,27 @@
     (-schema [_ type] (-schema @registry* type))
     (-schemas [_] (-schemas @registry*))))
 
-(defn composite-registry [& ?registries]
+(defn composite-registry
+  "Return a Registry backed by the ?registries. Registries further left take precedence."
+  [& ?registries]
   (let [registries (mapv registry ?registries)]
     (reify
       Registry
       (-schema [_ type] (some #(-schema % type) registries))
       (-schemas [_] (reduce merge (map -schemas (reverse registries)))))))
 
-(defn mutable-registry [db]
+(defn mutable-registry
+  "Takes a deref'able db containing a ?registry, returning
+  a Registry that forwards to db's ?registry."
+  [db]
   (reify
     Registry
     (-schema [_ type] (-schema (registry @db) type))
     (-schemas [_] (-schemas (registry @db)))))
 
-(defn var-registry []
+(defn var-registry
+  "Adds support for Clojure vars."
+  []
   (reify
     Registry
     (-schema [_ type] (if (var? type) @type))