This documentary looks at 'session musicians' and side persons :) in bands. They did talk to Steve Lukather and Kenny Aronoff. They also looked at guys (and gal) who played on tours with Alice Cooper, Ozzy, Filter, Elton John, Metallica, Whitesnake, Pink, Billy Joel etc etc etc. Some interesting tales and a good look at a part of the business side of the music biz. Available on Netflix.