From my teaching experience I have noticed some confusion about modes and scales among players interested in improvisation. Part of this may be due the idea that there are two perspectives involved with thinking about them. So let’s break up these two perspectives and see if we can clear things up, at least a little. One perspective is to relate a group of notes to a key signature and then take the starting note to be a degree of that scale. For example if we have two sharps, F# and C# then begin and end with the pitch A, we have the Mixolydian mode. This is the key signature for D major which also has a modal name, Ionian. So if we start and end with the root note D we are playing Ionian. Let’s go over all seven of the modes associated with the major scale. Root is Ionian, two is dorian, three is phrygian, four is lydian, five is mixolydian, six is Aeolian, seven is locrian. As we can see if we count up from D we end up with A being the fifth letter or pitch. This is why A scale above has been identified as mixolydian in the example above. The second perspective is to relate the group of notes to the major scale (Ionian Mode) and describe it based on how it differs from that scale. In this example we would say that a scale with two sharps, F# and C#, beginning and ending with the pitch A, would have a flat 7 and like the previous example we call that mixolydian. The major scale has root, two, three, four, five, six, and seven; all natural. Do, re, mi, fa, sol, la, and ti. So playing a scale from A to A with two sharps, F# and C#, has a flat seven because the key of A has three sharps F#, C#, and G#. G# being the seventh has been lowered one half step to produce a G natural. I’ll list the modes in this way. Ionian is all natural. Dorian has flat three and flat seven. Phrygian has a flat two, flat three, flat six, and flat seven. Lydian has a sharp eleven. Mixolydian has a flat seven. Aeolian has a flat three, flat six, and flat seven, Locrian has a flat two, flat three, flat five, flat six, and flat seven. Understanding the two perspectives is important. In general, the first perspective mentioned is beneficial when thinking about the overall key of a piece of music. The second perspective is great for thinking about individual chords. Both perspectives are beneficial to utilize when thinking about chords and tonality. Working these ideas out on the guitar will help continue clearing up these concepts.