This month, The Birthday Party returns to the same theatre where it opened exactly 50 years ago. Slated by the critics, it nearly ended Harold Pinter's career. So how did it go on to become such a classic, asks Michael Billington
Giuseppe Arcimboldo's heads composed of fruit, flowers, birds and books are not just a gimmick, Jonathan Jones argues. They have a demonic life of their own, weaving together the art, science and occult of Renaissance Europe