With its acoustic and electric guitar, literal bells and whistles, and extremely active bonding with the action on screen, this was a truly revolutionary score.

I have to imagine that the crystalline electric guitar sound heard here did as much to move sales of the instrument as popular rock bands did.

Like many Morricone scores, this one exploits the potential of a single theme. But what a theme! The main title has arpeggiated acoustic guitar backing up a whistled melody that soars up and down like a bird riding air currents. Then piccolo comes swirling in, percussion that starts extremely sparsely and builds very gradually. Then a male chorus and one of the all-time great electric guitar sounds for one of the all-time great electric guitar lines, perhaps not as well known as the James Bond riff but certainly its equal in quality.

Some of the rhythmic ideas are moved to piano for "Quasi Morto", with staccato playing that anticipates some of Jerry Goldsmith's work down the road, particularly for the Rambo movies.

"Musica Sospesa" uses long tones from flute and organ and short, sharp notes from guitar and percussion to create some uneasy feelings. After this comes a very heavy and shadowy "Square Dance" cue that doesn't really sound fun or easygoing at all.

Some very weight and dramatic music introduces "Ramon", the villain of the piece. It sounds funereal and the mood is not at all lightened in the next cue, more long, heavy, shadowy tones for "Consuelo Baxter".

The main theme then gets another run-through for "Doppi Giochi", followed by "Per Un Pugno Di Dollar (#1)", the movie's secondary theme, an ancestor of "The Ecstasy of Gold", still a few years away. This is classic "walking to the final battle" music.

Snare with some subtle electric guitar or bass guitar kick off "Scambio Di Prigioneri", soon joined by trumpet and strings and female chorus for another tense track.

An abbreviated version of the main theme, which swerves into some unexpected harmonic territory follows with "Cavalcata" and then gets reprised with a much busier and lighter feel in "L'Inseguimento".

Morricone could cover a lot of ground and this is displayed vividly in the almost ten minute-long track "Tortura", a suite of sonic surprises and orchestral color, merging the melodic with the avantgarde and bringing in elements you'd expect to hear from a horror or fantasy movie score. If someone hasn't written a monograph just about this piece yet, why not?

After that comes a kind of march piece, with pounding snare drum, lots of sharp notes and swelling crescendi/descrescendi, again anticipating some famous movie music we would all love in future decades.

"Senza Pietà" starts quietly and peacefully and then takes off for "and now we ride!" energy at the end.

Very off-kilter rhythm and seesawing parts from harmonica, violin, percussion (especially gong), with electric guitar and piano and other instruments doing monomaniacal and relentless ostinati create a brilliant landscape for "La Reazione".

After that there are two reiterations of the two main themes and we're done.

There are several reasons why this movie and others that followed were so successful and the music has always been one of those reasons.