There are several Quests throughout the game. Only the main quest must be completed, but as is typical with RPGs the side quests offer additional experience, gold, and rewards.
“Before I start, I'd like to say that this guide is far from perfect, but will hopefully help...Allen Guide (character)
“The main quest involves chasing Duke Marduk through the Philospher's Tower. New Weapon - Get...MainQuest
“Throughout the tower you will find books which contain Lost Memories. Collecting them reveals...Lost Memories
“Historian Theodore in the Library will give you a variety of quests looking for old books. Some...HistorianQuests
“Yuna in the Library provides a number of quests that involve finding a flower in the tower...Flower Quests
“Alchemist Flamel in the Village gives a number of quests relating to Alchemy. The first quest is...AlchemyQuests
“A cool and calm Traveller offers a number of quests based on his desire for revenge from...RevengeQuest