Even on a gray day in Paris last week, there was one place you could find a crowd of tourists from places as varied as Rome, Tokyo and Orlando, Florida — gathered at the Pere Lachaise cemetery, around the graveside of Jim Morrison. Forget Chopin, Oscar Wilde, and the hundreds of other luminaries interred among its chestnut trees, the frontman of The Doors has long been the cemetery's headline draw. Part of the attraction is the almost mystical magnetism he exuded in life; part is the macabre mystery of his demise: How did one of the legends of the rock...