In the late 80s there were no GTA games in the world. Not a single game had been made with that title. At some point in the 90s the first one was made. Then they made a London add-on for it which they really should do again with one of the new games. After that they made a proper sequel. I don’t remember that having any add-ons or anything they just went straight to GTA 3. The third one had loads of spin-offs and I just lost track. Finally they made a proper sequel and the latest spin off of the series is China town Wars on the DS.