James MacMillan: Berserking

  
""Berserkers" were special warriors common to the Vikings and the ancient Celtic tribes, who would work themselves into a frenzy with mead, mushrooms and hyperventilation to achieve performances of ferocious courage in battle. Although deadly in combat, the berserking process was paradoxically a suicidal one since, having lost their senses, they were vulnerable to a more stealthy attack... But this piano concerto is not programme music. Instead, the abstract subject matter (in this case misplaced energy) has become the defining element in the work’s material and structure."
James MacMillan