Goblin Engineering

Goblin Engineering is one of two disciplines engineers may specialize in upon attaining level 30 and 200 skill. (The other is Gnome Engineering.) Its innovation is diverse with items ranging from Goblin Rocket Helmet and Goblin Bomb Dispenser to The Big One. This diversity can give Goblin Engineers the element of surprise and situational advantages when facing enemies.

Becoming a Goblin Engineer
Much like with Gnome Engineering, this is a three step process.

The referral
You first have to get a referral from an engineering trainer. There are a number of people who will give you a referral. Remember, you do have to have 200 skill, and be at least level 30 to be eligible.
 * The referral quests: Goblin Engineering.

The pledge
The person you are sent to is Nixx Sprocketspring, in Gadgetzan, Tanaris. He will hand you an unsigned pledge, and ask that you sign and return it. This seals your commitment to Goblin Engineering.
 * The Pledge of Secrecy (Tanaris)

Showing your work
Nixx will then ask you to show examples of your work. You will be handing over:
 * 20x Big Iron Bomb
 * 20x Solid Dynamite
 * 5x Explosive Sheep

Raw mats: 2x Silver Bar 30x Iron Bar 40x Heavy Stone 20x Solid Stone 10x Silk Cloth 20x Wool Cloth 20x Bronze Bar 5x Medium Leather

Having done that, you are issued your Goblin Engineer Membership Card, which entitles you to training on the 'goblin engineer only' engineering recipes. Congratulations! You have specialized in Goblin Engineering!

Your membership card
Prior to the release of WotLK, having completed the exercises above, you were given a Goblin Engineer Membership Card. It remained valid for 14 days of 'played time', not 14 real days.

If you ever found yourself without this card, you could pay 2 gold in dues to the Goblin Engineering trainer (still Nixx Sprocketspring) and get a new one. Since the release of WoTL, Goblin Engineering is added to your book as a skill.

An added benefit of renewing your membership prior to patch 3.2.2 was that you would be sent a renewal gift of some useful engineering schematic. Schematic: Pet Bombling formerly could only be acquired this way. However, this item now drops in Gnomeregan.

Goblin Engineering items

 * Goblin Engineering items require specialization in Goblin Engineering to craft.
 * Some Engineering items which have 'Goblin' in the title do not require specialization to craft or use, e.g. Goblin Jumper Cables.
 * While some Goblin Engineering items require specialization to use, others do not. Some are tradable, some are BoP.

Switching specializations
To switch between Goblin Engineering and Gnome Engineering, bring up the “Professions” tab in the “Spellbook & Abilities” interface. Within the “Engineering” section, on the top-right side, there will be a button for your current specialization. Immediatedlty to the left of that button will be a small red circular icon. You can click that icon to remove your current specialization. Important: Do not click the similar icon that is to the left of the green skill bar since that would completely remove your Engineering skill (and not just the specialization).

Once you have removed your specialization, the Engineering trainers in your faction’s home city should offer you the choice of specializations quests: Gnome Engineering (quest), Goblin Engineering (quest).

From patch 3.2.0 until Cataclysm, Gnomish Engineers and Goblin Engineers could switch profession specializations for by visiting Narain Soothfancy's hut in northeast Tanaris and interacting with the book on the table.

Quotes
''It might not work ALL the time, but what kind of goblin engineer are you! If survival was your first priority you could never be a real Goblin Engineer!'' — Zap Farflinger

From the Manual of Engineering Disciplines:

"You want to know about goblin engineering? Try asking one of their best and brightest engineers about it - I think his name is 'Nubby Stumpfingers'.  Want to know why he's named that?  THAT'S goblin engineering." — Ringo Tragediction, gnome engineer

"Say what you want about us goblins, but I will tell you this: WE HAVE EXPLOSIVES!" — Yazz Nitrospork, goblin bombardier