Items that replenish low HP and MP, cure various ailments and information about the ever-elusive "Right of Hope".
Items that permanently increase your characters statistics, and info on where to find them.
Items your characters can equip, and where to find them.
Items which can only be used in battles, and where to find them.
Items used to promote your characters to a special class, and where to find them.
Items which are fundamental to the story, along with their purposes and locations.
Where to find all of the 15 pieces of mithril, and what they're used for. Plus, a very plausible theory as to why there are 15 pieces of mithril in the game.