What is the Guide Book used for? I used Morph on one of the sunken ghost ship things in the underwater reactor, and it turned into a Guide Book. But I can't sell them, use them in battle, use them in the field, or do anything else with them. What are they good for? It says that they're a map from a different world that sunk with an ancient ship, or something like that. But what do I do with it?

Take it back to the old man in Kalm and he'll give you the underwater materia so the time limit is removed in the Emmy Weap. battle.

give it to the guy in the house to the right in kalm on the second floor and he'll give you the underwater materia that removes the time limit in the emerald weapon battle

question, where do you get morph to get the guidebook?

The Morph materia is found at the Temple of the Ancients, near the purple pool of consciousness that Aeris touches to locate Sephiroth.

There are three things you can trade with the Kalm Traveller.

Guide book - get by morphing ghost ship - you get underwater materia for it

Earth harp - get by defeating emerald weapon - you get one of every type of master materia eg master command, master magic, master summon

Desert rose - get by defeating ruby weapon - you get a gold chocobo for it