After watching a TV program on Spike Milligan's battle with depression, John Lennon sent the comedian a book. In the comments on the John and Mimi post, @Karen and some others have elucidated a theory that I've toyed with for years, myself: that John Lennon, Chief Beatle and beloved by all denizens of Dullblog, suffered from bipolar disorder. Formerly called manic depression, bipolar disorder is "a condition in which a person has periods of depression and periods of being extremely happy or being cross or irritable. In addition to these mood swings, the person also has extreme changes in activity [...]