Expert engineering yields two distinct disciplines: gnome and goblin.  Clearly, goblin engineering is the choice of all brilliant engineers.  Learn to master the world through the judicious use of high explosives and fantastic gear!$B$B$N, read this manual.  If you want to learn about goblin engineering, 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.