The opera Macbeth is a success or failure depending on the principals Macbeth and Lady Macbeth. Macduff makes some contribution while Banquo's part ends halfway through. The witches play an important role, the chorus do to a minor extent. The orchestra needs to be resounding where needed without overpowering the "parola scenica" or scenic word which is paramount in the opera based on Shakespeare, the poet so much admired by Verdi. Milnes (Macbeth) is not suited to the crucial role. His baritone middle and upper registers are somewhat hollow, hence not dark and sinister enough to plot with his wife the king's assassination and usurp the throne. Cossotto (Lady Macbeth) fares a bit better but with many hysterics and a poor legato. She is no Souliotis, vocally the finest Lady Macbeth.