diff --git a/src/backend_piston.rs b/src/backend_piston.rs
index 6a0e054..b3b2732 100644
--- a/src/backend_piston.rs
+++ b/src/backend_piston.rs
@@ -12,35 +12,46 @@ where TUserAction: Clone + Serialize,
     schema: Schema<Event, usize, TUserAction>,
 }
 
+/// Schema implementation using the Piston backend
 impl<TUserAction> SchemaPiston<TUserAction>
 where TUserAction: Clone + Serialize,
 {
+    /// Create a new Schema with given name
     pub fn new(name: &str) -> Self {
         SchemaPiston {
             schema: Schema::new(name)
         }
     }
 
+    /// Assigns assigns the controller from next registered input event
+    /// to this schema if it passes through the input flags
     pub fn assign_controller(&mut self, event: &Event, iaf: InputTypeFlags) -> bool {
         self.schema.assign_controller(event, iaf)
     }
 
+    /// Assigns specified user action to the next registered event from piston
     pub fn assign_input(&mut self, event: &Event, action: TUserAction, iaf: InputTypeFlags) -> bool {
         self.schema.assign_input(event, action, iaf)
     }
 
+    /// Main event processing hook. Will result in ProcessingResult for user's action if
+    /// a mapping is withing the schema for the given event.
     pub fn process_event(&mut self, event: &Event) -> Option<ProcessingResult<TUserAction>> {
         self.schema.process_event(event)
     }
 
+    /// Assigns a player_id to this schema
     pub fn set_player_id(&mut self, player_id: Option<usize>) {
         self.schema.set_player_id(player_id);
     }
 
+    /// Returns the current player_id (or None if not assigned)
     pub fn player_id(&self) -> Option<usize> {
         self.schema.player_id
     }
 
+    /// Returns the currently assigned controller (or None if not assigned)
+    /// *NOTE* keyboard and mouse have no controller ID by definition in piston
     pub fn controller_id(&self) -> Option<usize> {
         self.schema.controller_id
     }