I was replying to a request in another thread (regarding the Mixolydian mode) as follows: Well, the "church" modes - I had a look at the current Wikepdia exposition this morning and got the impression of it being too detailed and thorough for a "primer" by far. I will be happy to explain it myself but I have to be busy vocationally this day. If you have a piano keyboard at hand you might just try to play 8-note-scales starting from different notes, thereby never quitting the "white" keys. There you'll have them, the modes. If we ignore the last one - from B to B - for the moment they are six. Three of them allow to built major chords on the root note, three of them allow to built minor chords instead. It's just an extension of the major/minor concept (you know: "natural" Amin as being "parallel" to Cmaj due to sharing all of their notes). The next common mode might be the Dorian one (from D to D using just white keys). It's the world of "Scarborough Fair" and the likes. I have to leave it at that for the moment - you might check out this site as a starting point.
I then suggested creating a separate topic for discussing these casually recurring questions which I do herewith.
Best regards to all - Wolf
edit: typo from the original post corrected