The Major scale is dominant in western music, however, there are many other, less common scale types which also play a significant role in different areas of western music, and several others besides that are widely used in the music of other cultures.

While music can be written directly in one of any these scale, they are also often used as the framework for improvisation, the playing of a spontaneous melody line over a backing chord sequence.

1. The Minor Scales :

The Harmonic Minor and Melodic Minor scales are both distinguished from the Major scale by the semitone (rather than tone) interval between the second and third notes. The difference between the Harmonic and Melodic Minor scales is the second last interval - the Melodic Minor uses a 6 degree, like the Major, while the Harmonic Minor contains the extra alteration of this being a b6 degree.

2. Pentatonic & Blues Scales :

The Major Pentatonic, Minor Pentatonic and Blues scales are common choices for improvising with rock and blues.  The pentatonic scales contain 5 notes, and the blues scale contains 6 notes.
 
 

 The intervals in these scales fit in well with blues chord progressions, which usually include a liberal amount of dominant seventh (7).
 
 
 

3. The Symmetric Scales :

The Whole Tone and Diminished scales are called symmetric scales, a term used for scales where more than one root note will result in the same set of notes.
 
 

The Diminished scale is slightly more complex in nature and sound, with alternating semitone and tone intervals.  There are three distinct sets of notes which this scale can produce, depending on the root note.

4. Bebop Scales :
Both the Major Bebop and Dominant Bebop scales are based on the Major scale, but with an extra note added, giving a characteristic chromatic run of three notes separated by a semitone.
 
 

These scales started to appear in jazz improvisation in the 1960's (Bebop itself is a style of jazz) as a way of achieving a more melodically interesting and complex sound.
 
 
 

5. Exotic Scales :

These exotic scales are used in music of Eastern Europe, Asia and the Middle East.  Although not often appearing in western music, it is useful to compare them to the other scales.
 
 

 All these scales make a distinctive sound.  When played, they can evoke strong echoes of the traditional or contemporary music originating from these cultures.
 
   

6. Major Scale Modes :

We can arrange the notes of the Major scale in seven different ways, each starting on a different note of the Major scale.  These related scales are known as the modes of the Major scale.

All of the modes of the Major scale are shown below.  (The standard sequence of intervals of the Major scale that we have used until now is called the Ionian mode. Remember that the modes of the Major Scale are all based on the same fundamental set of intervals, which are just shifted by one position between each mode. 

The modes of the Major scale are most widely used in jazz and rock improvisation. They are useful because each mode tends to fit well with particular chord types.

At first, modes may seem to introduce an extra-complexity, but their value is in providing more handles for the Major scale. An accomplished musician may quickly select an appropriate mode for improvising over a particular chord.