A book for divination; book of omens.
They are always handwritten usually in Arabic script and in the Tausug language. Some have the contents arranged according to days, months and hours. Some have a string attached to the back which is used as place marker. The place marker is inserted somewhere and wherever the book opens, from that page one finds out if a planned journey is opportune or on what day one should start on it, etc. It is consulted for just about anything like planting, selling, buying, building a house, etc.
When he is going to go somewhere, he first looks at his book of omens.