From the Playbill - Director 's Notes:
To paraphrase Maria's letter to Malvolio in Twelfth Night: "Some are born, evil, some achieve evil, and some have evil thrust upon them."
What is evil? From whence does it come? What are the factors? Who knows the formula for the diabolical? No one. Hence the fascination with biographies of serial killers, African dictators, and Adolf Hiter. Indeed a friend of mine refers to he History Channel as the 'Hitler Channel,' so frequently are stories about Der Fuhrer with black and white footage of the nefarious Nazis aired on that channel.
Certainly Shakespeare was interested in the question, as philosophers have been for centuries and as all great dramatists must be. Iago, Richard of Gloucester, Edmund the Bastard - to name a few - are no sweethearts. But in no other does Evil, with a capital E, so predominate as in Macbeth. Indeed, the elements of evil, the three weird sisters, are the first thing we see on stage, picking over the corpses on the still smoking battlefield, severing body parts for their potions and planting the seed of evil in the courageous and newly victorious Macbeth as Banquo, his comrade-in-arms, watches and listens in horror and fascination. The loyal general, "too full of the milk of human kindness" is infected.
-Robert S. Currier, Director