When they say comprehensive, they mean it. Assuming you can process this tome, you'll know probably more than you'll ever need for a job, theory-wise. With the proper technique to back it up, I'd say a strong familiarity with this text would put you in a pretty good place to instruct welding courses. I'll admit I skipped the sections on laser welding, explosive welding, & various other special processes, because well, I'll probably only pick up an Oxy-acetylene torch or arc equipment, but hey if you're interested it's all in here.