+#### 0.1.2 The default layer
+The **default layer** is the base keymap layer (0-31) which is always active and considered the "bottom" of the stack. When the firmware boots, the default layer is the only active layer. It is set to layer 0 by default, though this can be changed ~~in *config.h*~~ via Boot Magic settings.
+
+ Initial state of Keymap Change base layout
+ ----------------------- ------------------
+
+ 31 31
+ 30 30
+ 29 29
+ : :
+ : : ____________
+ 2 ____________ 2 / /
+ 1 / / ,->1 /___________/
+ ,->0 /___________/ | 0
+ | |
+ `--- default_layer = 0 `--- default_layer = 1
+ layer_state = 0x00000001 layer_state = 0x00000002
+
+Note that the `default_layer_state` variable only determines the lowest value to which `layer_state` may be set, and that `default_layer_state` is used by the core firmware when determining the starting value of `layer_state` before applying changes. In other words, the default layer will *always* be set to *on* in `layer_state`.
+
+The default layer is defined in the firmware by the `default_layer_state` variable, which is identical in format to the `layer_state` variable explained above. The value may be changed using the following functions:
+
+- `default_layer_state_set(state)` sets the state to the specified 32-bit integer value.
+- AND/OR/XOR functions set the state based on a boolean logic comparison between the current state and the specified 32-bit integer value:
+ - `default_layer_state_and(state)`
+ - `default_layer_state_or(state)`
+ - `default_layer_state_xor(state)`
+
+For example, to set layer 3 as the default layer:
+
+```C
+// convert 3 to a 32-bit unsigned long value, and set the default layer
+default_layer_state_set(1UL<<3);
+```
+