Final Fantasy Tactics was released in 1997 in Japan and 1998 in North America for the original Playstation. It is the first game to be set in the fictional world of Ivalice, which would later be the setting for several other games. Directed and written by Yasumi Matsuno, who had worked on the Ogre Battle series previously, Final Fantasy Tactics is an indepth tactical role-playing game set against the backdrop of a war between two major factions.
Gameplay in FFT takes place on an isometric field that can be freely rotated. Your primary character is Ramza Beoulve, who is accompanied by recruitable units, all of whom you can train in various disciplines (jobs). Customization is key to the gameplay, and you have mostly free reign to train your army as you see fit.
FFT is notable in the series for its difficulty, particularly near the start of the game; it's easy for players to get stuck on a particular early game mission, or a later gauntlet of battles that can prove impossible to beat for an ill-equipped group. If you play it, the biggest recommendation anyone can give is to keep multiple save files, just in case you get stuck and need to go grind.
In 2007, the game was rereleased as Final Fantasy Tactics: The War of the Lions, for the Playstation Portable. This version was later ported to mobile devices as well. If you're going to play the game, this is the version I recommend; the translation is much better and there are gorgeous animated sequences to accompany key cutscenes.