French composer Olivier Messiaen presented the "modes of limited transposition" in his book "La technique de mon language musical" (The Technique of my Musical Language).
What makes these scales special, is that they have a degree of symmetry, which causes the intervallic structure to be identical in two or more different keys.
The Whole Tone Scale for example, essentially only has two different keys. A whole tone scale consists of six notes, and is completely identical in six different keys.
Check out these wonderful videos of Nelson Veras at a clinic at the Conservatory of Amsterdam.
Structure: H - W - H - W - H - W - H - W
Transpositions: 3
Intervals: 1 - b2 - b3 - 3 - #4 - 5 - 6 - b7
Structure: W - H - H - W - H - H - W - H - H
Transpositions: 4
Intervals: 1 - 2 - b3 - 3 - #4 - 5 - b6 - b7 - 7
M6: Messiaen Mode 6
Structure: W - W - H - H - W W - H - H
Transpositions: 6
Intervals: 1 - 2 - 3 - 4 - #4 - #5 - b7 - 7
All M6 Scales
C |
M7: Messiaen Mode 7
Structure: H - H - H - W - H - H - H - W - H
Transpositions: 6
Intervals: 1 - b2 - 2 - b3 - 4 - #4 - 5 -b6 - 6 - 7
All M7 Scales
C |