To take a backward glance at the amazing kaleidoscope of change which has characterised so much artistic activity since the turn of the century, to look down from our present vantage point over the richly patterned landscape, indistinct and volatile, of the evolving ideologies, schools and styles, is to watch an inexorable tide of dark waters rising above a peaceful land, covering gardens, orchards, villages and churches, flowing in fast streams and eddies, linking and dispersing, fingers of flood groping forward, when unable to flow no further—dissipating, joining further washes pressing forward, swelled by secondary streams, a total immersion of previous landmarks, drowned in the rising waves, a saturation of ideas, a primordial cleansing, destruction, obliteration, finally—regeneration.