The opening strains of Max Steiner's strings as technicolor images of the Old South and the words Gone With The Wind sweep across the screen.
The building crescendo of Bernard Herrmann's orchestral cacophony as we ready ourselves to enter the cloak and dagger world of North by Northwest.
Or the simple bass chords that signal impending doom as the camera moves through the shallows in the opening of Jaws.
Some movies have music that accompanies the opening credits and some movies have music that sets the mood. The above three are examples of scores that do more than give the movie a 
musical sound or provide something to listen to as the credits roll, they set the mood for what we're about to see. Two years after Jaws, John Williams would create a bombastic triumphal score that would never make for a nice, relaxing evening by the fire but boy did it set the mood for Star Wars. From the opening blare of the full orchestra the music told us, "This is not going to be a low-rent grainy serial chapter, this is going be a space adventure - A Big One."
I have music from movies that I like to listen to outside the films themselves. Scores that contain all the incidental music and cues contained in the film but without the surrounding action. Usually, but not always, they are not the type of music listed above. For me, when a score does a great job of setting the mood it becomes impossible to listen to it for any other purpose than accompanying the movie itself. Which puts me in the odd position of almost never wanting to listen to something I would consider a great score, because a great score to me (and I cannot stress this enough) does not have to be great music. It only has to be great in relation to what is on the screen. Thus I would classify Star Wars as a great score but, with many deep apologies to John Williams fans, I would not classify it as great music. I cannot imagine a moment in my life where I will one day pour myself a drink, bring out some brie and crackers by the fire and say to my wife, "Honey, put on the Star Wars score." I suppose I could imagine it, but in that version I have an odd twitch in my left eye and I drool a lot.
Which brings me back to setting the mood. Further on in this series I will be going into the full range of a score in relation to the movie but for this short post I wanted to take a minute to talk about the opening theme. Usually, but not always, the first piece of music you hear. And in the best cases, it sets the mood immediately. I remember as a kid watching and loving Forbidden Planet. I still do. I've seen it countless times and every time that opening music, with its bizarre assortment of Theremin-like electronic clicks and twangs and hums, lets me know I'm in for some pulpish sci-fi fun. In the credits it isn't even called a "score" or "music by" but "Electronic 
Tonalities by Louis and Bebe Barron."
Then there's the strings, and strings only, of Bernard Herrmann's score for Psycho. The familiar shrieking strings of the shower scene aren't there for the credits, but the music that is there has a propulsive sense of dread. If one went into the movie blind and missed the actual title, one would still have a pretty good idea of what kind of movie it was, if only in mood. And that's what we're talking about anyway.
And mood can sometimes be set after the fact. The first time one watches M (if one is unaware of the plot of the movie that is) the simple melodic notes of In the Hall of the Mountain King would tell the viewer nothing. It could be one of those Leni Riefenstahl mountain movies for all the viewer knows. But seeing M the second time, and each time after, the viewer knows the theme: It is the theme of the killer, the tune he whistles before the world closes in on him and he must kill again. And when those opening notes are heard, the viewer gets a chill.
As for the inverse it's fairly difficult to ruin the mood of a movie with only an opening theme, unless the music in incongruous throughout the film, and more likely than not movies that don't have great opening mood setting pieces simply don't need them. But it doesn't hurt to have them. There are so many great opening mood setting moments like the great use of Strauss over the title of 2001: A Space Odyssey that I'm sure I could do an entire post just listing them and fill this entire blog. But your sake and mine, I won't do that.
Instead let me close with two of my favorite mood setting openings. The first is from the great Michael Powell, Emeric Pressburger film The Life and Death of Colonel Blimp with music by Allan Gray. It's not precisely the first music in the movie. That occurs over the opening credits and sets its own tone. Rather it is the music that occurs directly following the credits as we watch motorcycle messengers deliver their urgent messages to individual base commanders. It immediately sets the mood that, while we know there will be serious story arcs involved, there will be plenty of mischievous fun to be had as well. And don't even get me started on how most of the opening doesn't make sense until the end when the flasback is complete which elevates the film to an even higher level - but that has nothing to do with the music anyway (I told you not to get me started).
Immediately following that is the opening credit sequence from The Shining by Stanley Kubrick. If that distorted Bartok music accompanying those dizzying shots of that tiny car amongst that vast mountainous landscape doesn't set the mood for what's to come I don't know what does. And interestingly, although I didn't notice it until after grabbing both scenes from their respective DVDs, I have chosen two opening sequences in which the music accompanies camerawork in constant forward movement. In both cases, the music and the shots propel us directly into the film.
