As we approach the fortieth anniversary special of "Saturday Night Live," -- Not to be confused with the 40th anniversary of "Saturday Night Live" -- it’s time to take stock of what makes the show so unique. 

Yes, the Not Ready For Primetime Players are key. So are the show’s writers. And hey, that whole “live” thing is still pretty important. But what about larger themes and trends? What disparate elements add up to the show as presently constituted? 

We’re going to break down “SNL” from A to Z, working the first half of the alphabet this week and finishing up next Saturday, the night before NBC's big special (and nine months before the actual anniversary).

Check out A to M...