There are as many rumors about Morrison's death as there are burnt-out hippies wandering the earth. The most widely accepted of these states that Morrison's death came after a heroin overdose. The problem with this theory is that Jim, while a fan of virtually every drug ever discovered, had a pathological hatred for heroin and frequently battled with Courson over her use of the drug. One variation on this theory states that Courson gave him some heroin to snort and told him it was cocaine.
Other theories have Morrison OD'ing on any number of other substances, including cocaine and alcohol, or choking on his own vomit after too much of the same. Further out on the fringe, some claim Morrison was assassinated by the Central Intelligence Agency for being a subversive influence, which seems like a bit of stretch.
The best theory about Morrison's death is, of course, that it never happened. Months before the Paris trip, Morrison had talked to friends at some length about his intention to fake his own death, leave his stardom behind and travel to Africa to live among whatever primitive peoples he imagined he could find there. He told people that he would send a message under the pseudonym, Mr. Mojo Risin', an anagram for "Jim Morrison" featured musically in "L.A. Woman."
Given the unusual circumstances of his death and the dearth of witnesses, the rumor that Morrison lives on has persisted. The surviving Doors occasionally take a shot at capitalizing on the idea by expounding their thoughts, but no one has reported receiving a telegram from Mr. Mojo Risin'. At least, not yet. On the other hand, even if Morrison didn't die in 1971, he would be 60 today. Given his insane habits, it seems quite likely that the Grim Reaper would have caught up with him by now, either through misadventure, overdose or simply bad living.