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+## Simpler Apps
+
+To build a re-frame app, you:
+  - design your app's data structure (data layer)
+  - write and register subscription functions (query layer)
+  - write Reagent component functions (view layer)
+  - write and register event handler functions (control layer and/or state transition layer)
+
+For simpler apps, you should put code for each layer into separate files:
+```
+src
+├── core.cljs         <--- entry point, plus history
+├── db.cljs           <--- schema, validation, etc  (data layer)
+├── subs.cljs         <--- subscription handlers  (query layer)
+├── views.cljs        <--- reagent components (view layer)
+└── events.cljs       <--- event handlers (control/update layer)
+```
+
+For a living example of this approach, look at the [todomvc example](https://github.com/Day8/re-frame/tree/master/examples/todomvc).
+
+### There's A Gotcha
+
+If you adopt this structure there's a gotcha. 
+
+events.cljs and subs.cljs will never be `required` by any other namespaces. To the Google Closure dependency mechanism it appears as if these two namespaces are not needed and it doesn't load them.
+
+And, if the code in these namespaces does not get loaded, the registrations in them never happen. You'll be baffled as to why none of your events handlers are registered.
+
+Once you twig to what's going on, the solution is easy.  You must explicitly `require` both namespaces, `events` and `subs`, in your `core` namespace. Then they'll be loaded and the registrations will occur as the loading happens. 
+
+## Larger Apps
+
+Assuming your larger apps has multiple "panels" (or "views") which are relatively independent, you might use this structure:
+
+```
+src
+├── panel1
+   ├── db.cljs           <--- schema, validation, etc  (data layer)
+   ├── subs.cljs         <--- subscription handlers  (query layer)
+   ├── views.cljs        <--- reagent components (view layer)
+   └── events.cljs       <--- event handlers (control/update layer)
+├── panel2
+   ├── db.cljs           <--- schema, validation. etc  (data layer)
+   ├── subs.cljs         <--- subscription handlers  (query layer)
+   ├── views.cljs        <--- reagent components (view layer)
+   └── events.cljs       <--- event handlers (control/update layer)
+.
+.
+└── panelN
+```
+
+## What About Navigation?
+
+How do I switch between different panels of a larger app?
+
+Your `app-db` could have an `:active-panel` key containing an id for the panel being displayed.
+
+
+When the user does something navigation-ish (selects a tab, a dropdown or something which changes the active panel), then the associated event and dispatch look like this:
+
+```clj
+(re-frame/reg-event-db
+  :set-active-panel
+  (fn [db [_ value]]
+    (assoc db :active-panel value)))
+
+(re-frame/dispatch 
+  [:set-active-panel :panel1])
+```
+
+A high level reagent view has a subscription to :active-panel and will switch to the associated panel.
+```clj
+(re-frame/reg-sub
+  :active-panel
+  (fn [db _]
+    (:active-panel db)))
+
+(defn panel1
+ []
+ [:div  {:on-click #(re-frame/dispatch [:set-active-panel :panel2])}
+        "Here" ])
+
+(defn panel2
+ []
+ [:div "There"])
+
+(defn high-level-view 
+  []
+  (let [active  (re-frame/subscribe [:active-panel])]
+    (fn []
+      [:div
+       [:div.title   "Heading"]
+       (condp = @active                ;; or you could look up in a map
+         :panel1   [panel1]
+         :panel2   [panel2])])))
+
+```
+
+## What About Event Ids?
+
+As an app gets bigger, you'll tend to get clashes on event ids.   One panel will need to `dispatch` an `:edit` event and so will another, but the two panels will have different handlers. 
+So how then to not have a clash? How then to distinguish between one edit event and another?
+
+Your goal should be to use event-ids which encode both the event itself (`:edit` ?) and the context (`:panel1` or `:panel2` ?). 
+
+Luckily, ClojureScript provides a nice easy solution: use keywords with a synthetic namespace. Perhaps something like `:panel1/edit` and `:panel2/edit`. 
+
+You see ClojureScript allows the namespace in a keyword to be a fiction. I can have the keyword `:panel1/edit` even though `panel1.cljs` doesn't exist. 
+
+Naturally, you'll take advantage of this by using keyword namespaces which are both unique and descriptive.
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