I read "From Wooden Wings" last night and didn't fully grasp the B-Scale pay that was referred to many times including 4 times in the short conclusion.

"The degrading B- scale must end."
"However the hated B-scale, although only a fraction of the scope Ferris and the board envisioned, still plagues this company."
"As Warren Villareal, UAL-MEC No B –Scale Committee Chairman recently said, 'The B-scale salary structure was not just an assault on the new hire pilots, it was an assault on the A-scale pilots.'"

Can someone point me to some reading where I can learn more about what that is; Why it's bad; Is it still here?