Expert engineering yields two distinct disciplines: gnome and goblin.  I only bother to mention goblin engineering because I'm a fair trainer.  They like to make things that blow up, and they rarely care what is in the way - even themselves.$B$B$N, read this manual.  If you want to learn how to blow yourself up, then take it to Nixx Sprocketspring in Gadgetzan.   Remember - membership is permanent and prevents joining the other discipline, so make sure this is what you want before finishing his task.