diff --git a/2_background/X_android.typ b/2_background/X_android.typ
index 9c7f6b0..3a19271 100644
--- a/2_background/X_android.typ
+++ b/2_background/X_android.typ
@@ -2,4 +2,15 @@
 
 == Android <sec:bg-android>
 
-#todo[Present the android environnement]
+Android is the smartphone operating system develloped by Google.
+It is based on a Long Term Support Linux Kernel, to which patches are added patches develloped by the Android community.
+On top of the kernel, Android redeveloped many of the usual components used by linux-based operating systems, and added new ones.
+Those change make Android a verry unique operating system.
+
+=== Android Applications <sec:bg-android>
+
+#todo[Include bg from class loader in the middle]
+
+
+
+=== Android Runtime <sec:bg-art>