Probably composed in late 1606 or early 1607, Macbeth is the last of Shakespeare's four great tragedies, the others being Hamlet, King Lear and Othello. It is a relatively short play without a major subplot, and it is considered by many scholars to be Shakespeare's darkest work. Lear is an utter tragedy in which the natural world is amorally indifferent toward mankind, but in Macbeth, Shakespeare adds a supernatural dimension that purposively conspires against Macbeth and his kingdom. In the tragedy of Lear, the distraught king summons the goddess of Chaos, Hecht; in Macbeth, Hecate appears as an actual character.
On the level of human evil, Shakespeare's Scottish tragedy is about Macbeth's bloody rise to power, including the murder of the Scottish king, Duncan, and the guilt-ridden pathology of evil deeds generating still more evil deeds. As an integral part of this thematic web is the play's most memorable character, Lady Macbeth. Like her husband, Lady Macbeth's ambition for power leads her into an unnatural, phantasmagoric realm of witchcraft, insomnia and madness. But while Macbeth responds to the prophecies of the play's famous trio of witches, Lady Macbeth goes even further by figuratively transforming herself into an unnatural, desexualized evil spirit. The current trend of critical opinion is toward an upward reevaluation of Lady Macbeth, who is said to be rehumanized by her insanity and her suicide. Much of this reappraisal of Lady Macbeth has taken place in discussions of her ironically strong marriage to Macbeth, a union that rests on loving bonds but undergoes disintegration as the tragedy unfolds.