I've always had a mild interest in the basics of jazz guitar because I like the sound of the some of the chords they use (like the major 7th sound). I was recently surfing Amazon, and saw the book below pop up on my suggested list, used, for $5 shipped. Saw that it's apparently a really high level of some basics. Kind of a here are some ideas to play with to add some jazz-sounding ideas to your playing. So I ordered it. Came in the other day, so I sat down to start reading it this afternoon. Got through the first chapter that was basically talking about influential players and a recommended listening list (Django, Charlie Christian, Wes Montgomery, etc) and then got to the next chapter where they introduced the "basic" jazz chords. "Here's C7, Cmaj7, Cm7, and Cm(maj 7)." Wait...what?!? A minor major 7 chord? It's apparently a minor chord with a major 7 sound thrown in to create a dissonant sounding chord. It's actually a pretty recognizable sound that I've heard in old movies a LOT. A minor major 7 chord. Definitely not a sound we'd hear in blues at any point in time ever, but the fact that I now know it exists means that I think my mind has officially been blown today.