There's been loads of speculation as to the exact nature of the friendship between John Lennon and Paul McCartney; during and after The Beatles. And when I say "loads," it runs the gamut from former bandmates who recalled each other fondly from a distance to something encompassing a physical nature. What does seem clear is that between the two of them, while Paul's descriptions of their relationship stayed pretty constant, John's went from demonizing Paul in print and song to describing him as his best (male) friend. Somewhere in there lies a truth, and to help unearth it, my guest today is journalist and author Glenn Greenberg, who recently penned an 80th birthday magabook on John.