Classic cocktails are a little bit like ghosts: apparitions from bygone eras who have weathered the test of time, and who are not allowed to cross to the other side until their work in this mortal plane is complete. Originally commanded by great spirit guides of the 19th and 20th centuries, conjuring up one of these cocktails to do your bidding merely requires performing the proper incantations with your jigger, while uttering the commands from your bar necronomicon.
See also: Drink of the Week: Moonraker at Bar Agricole