Endgame studies

I have always had a real fascination for these, and still believe that the efforts spent in solving them can really pay off in terms of practical chess skills - in particular, they raise awareness of tactical possibilities during a game, they help to improve chess visualisation, and they help with 'imagination' in chess.
Here is an old favourite of mine:

White to play and win - the process involves gradually forcing the Black king down the board, followed by a pin driving the rook off the file. A full solution might appear here later!