Back in San Francisco during the 80's I hung out with a trio called "The Squares". I was friends with the bass player. The guitarist for the band was the unsung Joe Satriani. I thought the band was terrific and everyone knew Joe was exceptional. I started taking lessons with Joe, an hour and a half a week, in a knock off Japanese guitar shop on Rose Street in Berkeley (the other Berklee ;-). We literally sat on crates in the back of the shop for our lessons. Even then, Joe was very focused on theory and more of our lessons were about modalities. I remember during one of our lessons Joe said - 'Hey look at this - I discovered arpeggios' which was true.
It was also during time I bought one of his guitars which was a strat knock off from the import shop where we studied. It's a little hot rod - just a treble pickup and volume (what else is there? ;-). I still remember him playing that guitar at the Stone - a club on Broadway in San Francisco - with it's mirrored pick guard flashing in the lights.
Joe played through a stereo chorus to two Echoplex tape delays into two half stack Marshall's at the time.
I was able to join Joe at Hyde Street Studios while he was recording his first solo album which was the beginning of the grander Satriani story.
I've attached a few of the theory lessons Joe wrote out for me.

Hey thanks for sharing your story. That's so cool to see these handwritten scripts here.

How many students did he have back then and did you become friends with Joe ?

This really cool and a part of rock guitar history which you are sharing here - thanks