Reverse Engineering will drill down and search your tradeskills for their elements
It's just like Gnome Engineering! - Nixx Sprocketspring, Tanaris
It's just like Gobin Engineering! - Oglethorpe Obnoticus, Stranglethorn
Sometimes being an Engineer (or one of the other tradeskills) means you're fiddling with heaps upon heaps of separate little twiddly items before being able to build up your masterwork gadgetry. Reverse Engineering will turn you around on your head. Now you can work from a top down perspective. Simply open your Tradeskill panel up to the desired object, then click on the icon for any part that requires construction, and voila, you'll be scrolled directly to that item. Not only that, but there's a handy 'pop back' button that will pop you back up the stack to your previous location!
You'll be able to instantly see what parts are craftable by the cog indicator that will appear when you mouse over the item.