The flowers that they wore in their hair have long since wilted, but the generation that came of age in the 1960s will spend the coming months recalling a summer four decades ago, when rock music, drugs and sexual liberation fused to create the Summer of Love. From New York, where Janis Joplin's psychedelic Porsche is on display at the Whitney Museum of Art, to the Bay area, where Joplin's band, Big Brother and the Holding Company, will play at an anniversary tribute to the Monterey Pop music festival, the calendar will be flipped back to an earlier time that,...