Grand Theft Auto
"Grand Theft Auto", the first game in the series, was released for Microsoft Windows and MS-DOS in October 1997, ported to the PlayStation in 1998 and the Game Boy Color in 1999. "Grand Theft Auto 2" was released in 1999 for Microsoft Windows, later receiving ports on the PlayStation, Dreamcast and Game Boy Color.
Multi Theft Auto
The first version of "Multi Theft Auto", dubbed "Grand Theft Auto III: Alternative Multiplayer", attempted to fill in this gap by extending an already existing cheating tool with functionality that allowed the game to be played with a very crude form of two-player racing over a computer network purely as a proof of concept, similar to how the now-defunct XBAND service worked by manipulating game memory in order to add online multiplayer functionality. Newer versions of "Multi Theft Auto" with increasingly better gameplay and other improvements were released based on the same concept of game manipulation, by a small team of developers.